CHAPTER I
Anatomy
·
Study
of the structure and form of the human body.
Physiology
·
Study
of the function or behavior of the organs and other structures of the body.
Structural
Organization of the Body
1. Cell
·
Structural
unit of the body
2. Tissue
·
Groups
of similar cells
3. Organ
·
Group
of tissues organized into a unit and concerned with some specific function
4. System
·
Group
of tissues and organs arranged to perform some function
Composition
of Cells
1. Protoplasm
·
Name
used to indicate living matter
2. Body
Cells
·
Composed
of protoplasm, breathe, circulate contents, digest and absorb food, break down
complex molecules to produce energy, and build up new compounds to replace
those used up.
3. DNA
or Deoxyribose Nucleic Acid
·
Consists
of complete molecules located in the chromosomes of the nucleic of body cells.
4. RNA
or Ribose Nucleic Acid
·
A
compound molecule located in the nucleoli of cell nuclei or in the cytoplasm of
cells.
Parts of a
Cell
1. Cell
Membrane
·
Also
called plasma membrane, a very thin covering that surrounds each cells.
·
It
forms a wall to contain the cell contents but is permeable to water and many
molecules, allowing them to pass in or out of the cell.
2. Nucleus
·
A
centrally-placed rounded part of the cell that is separated from the remainder
of the cell by the nuclear membrane.
·
It
controls cellular activity and contains chromoomes and a small rounded granule,
the nucleolus.
·
Chromosomes
o Long threadlike filaments contained
within the nucleus.
·
Nucleolus
o Rounded body within the nucleus that
contains RNA molecules and protein.
3. Cytoplasm
o Part of a cell that lies outside the
nucleus.
·
Mitochondria
o Sausage shaped bodies, the power
plants, with enzymes producing chemical reactions that produce energy.
·
Endoplasmic Reticula
o Minute canals that build up proteins.
·
Golgi Bodies
o Minute vesicles, small sacs that
concentrate or condense intercellular material.
·
Lysosomes
o Minute droplets that digest proteins.
·
Centrosomes
o Small spherical bodies containing two
cylinders which take part in cell division.
·
Intracellular Fluid
o Fluid within the cytoplasm.
·
Other Granules
o Proteins, carbohydrates, fats,
pigments, etc.
The Cell Body
·
Consists
of the nucleus and surrounding cytoplasm.
Cell Processes
·
Projections
that extend out from the cell body in some types of cells, such as nerve and
bone cells.
Somatic Cells
·
A
term used to include all the cells of the body except the genetic
(reproductive) cells.
Genetic Cells or Reproductive Cells
·
Include
those cells that produce an embryo, the ovum, or egg in the female, and the
spermatozoon, or sperm, in the male.
Four Basic
Types of Tissues
1. Epithelial
Tissue or Epithelium
-
A
thin sheet of tissue composed of cells cemented together to form a covering or
lining membrane, such as skin, covering of a lung, or lining of a blood vessels
or in the intestine.
·
Pavement Epithelium
o Single layer of flat cobblestone or
tilelike cells.
·
Cuboidal Epithelium
o A layer of cube-shaped cells cemented
together.
·
Polyhedral Epithelium
o Many-sided cells that are cemented
together.
·
Goblet Cells
o Shaped like wine goblets, that is
found in columnar epithelium. They secrete mucus, a clear sticky colorless
fluid. And they are found in mucous membranes of the digestive tract.
·
Simple Epithelium
o Consists of a single layer of cells
cemented together to form a continuous sheet.
·
Stratified Epithelium
o Consists of several layers of cells
cemented together to form a membrane.
·
Endothelium
o A type of simple epithelium with a
single layer of cells forming the lining of blood vessels.
·
Mesothelium
o Another type of simple single-layered
epithelium that lines the body cavities, the pleura, pericardium, and
peritoneum.
·
Mucous Membrane
o Type of simple or stratified
epithelium that contains goblet cells and secretes mucus.
·
Serous Membrane
o Type of simple epithelium that
secretes a thin watery colorless fluid.
·
Synovial Membrane
o Type of epithelium that lines joint
cavities, bursae, and the sheaths of tendons.
2. Connective
Tissue
-
The
supporting and binding tissues of the body. Their functions are to support,
connect or bind other important tissues and to fill in spaces within and about
organs.
·
Loose (Areolar) Connective Tissue
o Consists of a semiliquid or jellylike
matrix surrounding well separated cells called fibroblasts.
·
Adipose (Fatty) Tissue
o A modified connective tissue.
·
Fibrous Tissue
o Type of connective tissue in which the
matrix consists of bundles of collagen fibers that either lie parallel to each
other or form a crisscross of fibers when in sheets.
·
Elastic Tissue or Elastic Connective
Tissue
o Largely composed of elastic fibers
that are contractile and strechable.
·
Reticular Tissue
o Composed of a fine network of fibers
and is located in the lymph nodes, spleen, thymus, and bone marrow.
·
Cartilage or Gristle
o Consists of oval shaped nucleated
cells surrounded by a matrix that cements the cells into a firm but flexible structure.
v Hyaline
Cartilage
o Forms articular cartilages at joints,
costal cartilages, nasal and laryngeal cartilages, and the ringlike cartilages
of the trachea and bronchi.
v Fibrocartilage
o Forms articular discs at some joints
such as the intervertebral discs, semi-lunar cartilages at the knee, wrist,
symphysis pubis, temporomandibular, and the acromioclavicular and
sternoclavicular joints.
v Elastic
Cartilage
o Forms the epiglottis, the cartilages
of the external ear, and of the auditory canals.
·
Bone or Osseous Tissue
o Modified connective tissue. It
consists of nucleted cells with many processes extending out from the cell
bodies like the legs of a spider.
3. Muscular
Tissue or Muscle Tissue
-
Compsed
of elongated, cylindrical or spindle-shaped cells cemented together to form
bundles or sheets.
·
Skeletal Muscle: Voluntary or Straited
Muscle
-
Usually
attached to bones across a joint. It contracts in response to messages
transmitted along motor nerves from the brain. It is called “voluntary” because
it may be made to contract at will.
·
Visceral Muscle: Involuntary or
Non-Straited or Smoothe Muscle
-
Found
in the walls of many hollow organs such as the stomach, intestine, gall
bladder, blood vessels.
·
Cardia Muscle or Myocardium
-
Type
of muscle found only in the wall of the heart.
4. Nervous
Tissue
·
Neurons or Nerve Cell
-
Consists
of a cell with a central nucleus and two sets of processes, an axon and
dendrites.
v Axon
o A single slender process extending out
from the cell body. It conducts nerve impulses away from the cell body.
v Dendrites
o Have several processes that often
extend out from the opposite pole of the cell body to the axon. They carry
impulses towards the cell body.
v Receptors
o Minute structures at the distal ends
of dendrites that pick up sensory impulses.
v Motor
Neurons
o Convey impulses from the brain and
spinal cord out to muscles or secreting glands thereby initiating contraction
or secreation.
v Effectors
o Minute plates or branching fibrils at
the distal ends of axons of motor neurons that transmit impulses to muscle
fibers or glands.
·
Neuroglia
-
The
supporting cells of the nervous system and are placed among and around neurons.
The Body Cavities
1. Ventral
Cavity
-
Formed
as the celom in front of the vertebral column.
1.1.Thoracic Cavity
-
Occupies
the upper part of the trunk and is enclosed by the chest wall. Between it and
abdomen is the double dome-shaped muscular partition called diaphragm.
1.2.Abdominal Cavity
-
Extends
from the inferior surface of the diaphragm to the pelvic bones.
1.3.Pelvic Cavity
-
Lying
within the bony pelvis is actually continuous with the abdominal cavity with no
separating partition between the two.
2. Dorsal
Cavity
-
Lies
within the skull and the vertebral column.
2.1.Cranial Cavity
-
Lies
within the cranium and contains the brain.
2.2.Spinal Canal
-
Extends
lenghtwise within the spinal column and contains the spinal cord.
Abdominopelvic Quadrants and Regions
·
Umbilical Region
-
The
centermost region which includes the umbilicus.
·
Epigastric Region
-
Immediately
superior to the umbilical region; overlies most of the stomach.
·
Hypogastric (Pubic) Region
-
Immediately
inferior to the umbilical region; encompasses the pubic area.
·
Iliac Region
-
Lateral
to the hypogastric region and overlying the superior parts of the hip bones.
·
Lumbar Region
-
Between
the ribs and the flaring portions of the hip bones; lateral to the umbilical
region.
·
Hypochondriac Region
-
Flanking
the epigastric region laterally and overlying the lower ribs.
Anatomical Position
-
The
subject stands upright, with the limbs extended, face to the front, palms of
the hands facing the front, and the feet together.
Lateral
-
Frequently
used as referring to the side of the body
or part of it.
Supine
-
The
position assumed when lying upon the back
with the face up, or if referring to the hands, with the palms up.
Prone
-
lying
face down, and palms directed downwards.
MEDIAL OR MESIAL
-
Part
of any structure or organ that lies nearest to the median line of the body.
LATERAL
-
Part
of an organ or structure that lies farthest away from the medial line of the
body.
ANTERIOR
-
Towards
the front or in the front part of the body.
POSTERIOR
-
Towards
the back, or in the back part of the body.
VENTRAL
-
Refers
to the front or anterior part.
DORSAL
-
Refers
to the back or the posterior part.
PALMAR
-
Refers
to the front or palm of the hand.
PLANTAR
-
Refers
to the sole of the foot.
VOLAR
-
Either
the palm of the hand or the sole of the foot.
SUPERIOR
-
Refers
to the upper part, or that part towards the head end.
INFERIOR
-
Refers
to the lower part, or that part away from the head end.
CEPHALIC
-
Refers
to the head or head end of the body or an organ.
CAUDAL
-
Refers
to the tail or tail end of the body or of an organ.
CEPHALAD
-
Towards
the head.
CAUDAD
-
Towards
the tail end.
PROXIMAL
-
Part
of a structure closest to its source or origin.
DISTAL
-
Part
farthest away from the source or origin or point of attachment.
LONGITUDINAL
-
Lengthwise,
along the long axis or length of a structure.
TRANSVERSE
-
Crossways,
or at the right angles to the long axis or length of a structure.
VERTICAL
-
Perpendicular
or at the right angles to the horizon, assuming that the subject is standing
up.
HORIZONTAL
-
Parallel
to the horizon, subject upright.
CENTRAL
-
The
inner part, farthest from the surface.
PERIPHERAL
-
On
or near the surface, outer part.
SUPERFICIAL
-
On
or near the surface.
DEEP
-
Far
from the surface.
MAJOR
-
The
larger or greater of two.
MINOR
-
The
smaller or lesser of two.
INTERNAL
-
On
the inside of the body.
EXTERNAL
-
On
the outside of, the outer part of the body.
INTRINSIC
-
Part
of an organ itself.
EXTRINSIC
-
Originating
outside an organ.
VISCERAL
-
Refers
to some organ
PARIETAL
-
Refers
to a wall, relating to a wall of a structure.
ANATOMICAL PLANES AND SECTIONS
PLANE
-
A
real or imaginary flat surface.
1.
Longitudinal
Plane
-
A
flat surface made by cutting lengthwise or along the axis of the body or a part
of it. The cut could be made from side to side, or from front to back, and with
the subject standing upright or lying down, or in any other position.
2.
Transverse
Plane
-
Flat
surface made by cutting through the body or part of it crossways, or at the
right angles to the long axis. The cut from front to back, or from side to side
would have the same result.
3.
Vertical
Plane
-
A
longitudinal plane made with the subject upright, and the cut made
perpendicular to the horizon, either from front to back or from side to side.
4.
Horizontal
Plane
-
A
transverse plane with the subject upright, and the cut made parallel to the
horizon.
5.
Midsagittal
or Median Plane
-
A
longitudinal plane made by cutting from front to back along the median line of
the body, and along the sagittal suture of the skull.
6.
Sagittal
Plane
-
A
longitudinal plane made by cutting from
front to back to one or other side of the sagittal suture, and parallel to the
midsagittal plane.
7.
Coronal
Plane or Frontal Plane
-
A
longitudinal; plane made by cutting lengthwise and from side to side through
the head and body or part of it along the coronal suture, or parallel to it.
8.
Subcostal
Plane
-
A
transverse plane made by cutting across the upper abdomen at right angles to
the long axis of the body, and opposite the 10th costal cartilages,
the lowest limit of the thoracic cage.
9.
Transpyloric
Plane
-
A
transverse plane made by cutting across the body from one side to the other at
the level of the 9th costal cartilages or half of way between the
upper end of the sternum and the symphysis.
CHAPTER II
- Matter
- Matter
is anything that occupies space and has weight.
- Matter
exist in three states: gas, liquid, and solid.
- Energy
- Energy
is the capacity to do work or to put matter into motion. Energy has
kinetic (active) potential (stored) work capacities.
- Types
of energy that are important in body functions include, chemical, electrical,
mechanical, and radiant.
- Energy
can be converted from one form into another, but some energy is always
unuseable (lost as heat) in such transformations.
- Elements and atoms
- Each
element is a unique substance that cannot be decomposed into simpler
substances by ordinary chemical methods. A total of 112 elements exist;
they differ from one another in their chemical and physical properties.
- Four
elements (carbon, hydrogen, oxygen, and nitrogen) make up 96% of living
matter. Several other elements are present in small or trace amounts.
- The
building blocks of elements are atoms. Each atom is described by an
atomic symbol consisting of one or two letters.
- Atomic structure
- Atoms
are composed of three subatomic particles: protons, electrons, and
neutrons. Because all atoms are electrically neutral, the number of
protons in any atom is equal to its number of electrons.
- The
planetary model of the atom portrays all the mass of the atom (protons
and neutrons) concentrated in a minute central nucleus. Electrons orbit
the nucleus along specific orbits. The orbital model also locates protons
and electrons in a central nucleus, but it depicts electrons as occupying
areas of space called orbitals and forming an electron cloud of negative
charge around the nucleus.
- Each
atom can be identified by an atomic number, which is equal to the number
of protons contained in the atom's nucleus.
- The
atomic mass number is equal to the sum of the protons and neutrons in the
atom's nucleus.
- Isotopes
are different atomic forms of the same element; they differ only in the
number of neutrons in the nucleus. Many of the heavier isotopes are
unstable and decompose to a more stable form by ejecting particles of
energy from the nucleus, a phenomenon called radioactivity. Such
radioisotopes are useful in medical diagnosis and treatment and in
biochemical research.
- The
atomic weight is approximately equal to the mass number of the most
abundant isotope of any element.
- A
molecule is the smallest unit resulting from the binding of two or more
atoms. If the atoms are different, a molecule of a compound is formed.
- Compounds
exhibit properties different from those of the atoms they comprise.
- Bond formation
- Chemical
bonds are energy relationships. Electrons in the outermost energy level
(valence shell) of the reacting atoms are active in the bonding.
- Atoms
with a full valence shell (2 electrons in shell 1, or 8 in the subsequent
shells) are chemically inactive. Those with an incomplete valence shell
interact by losing, gaining, or sharing electrons to achieve stability
(that is, to fill the valence shell).
- Ions
are formed when valence-shell electrons are completely transferred from
one atom to another. The oppositely charged ions formed attract each
other, forming an ionic bond. Ionic bonds are common in salts.
- Covalent
bonds involve the sharing of electron pairs between atoms. If the
electrons are shared equally, the molecule is a nonpolar covalent
molecule. If the electrons are not shared equally, the molecule is a
polar covalent molecule. Polar molecules orient themselves toward charged
particles.
- Hydrogen
bonds are fragile bonds that bind together different parts of the same
molecule (intramolecular bonds). They are common in large, complex
organic molecules, such as proteins and nucleic acids and between water
molecules.
- Patterns of chemical reactions
- Chemical
reactions involve the formation or breaking of chemical bonds. They are
indicated by the writing of a chemical equation, which provides
information about the atomic composition (formula) of the reactant(s) and
product(s).
- Chemical
reactions that result in larger, more complex molecules are synthesis
reactions; they involve bond formation.
- In
decomposition reactions, larger molecules are broken down into simpler
molecules or atoms. Bonds are broken.
- Exchange
reactions involve both the making and breaking of bonds. Atoms are
replaced by other atoms.
- Inorganic compounds
- Inorganic
compounds making up living matter do not contain carbon. They include
water, salts, acids, and bases.
- Water
is the single most abundant compound in the body. It acts as a universal
solvent in which electrolytes (salts, acids, and bases) ionize and in
which chemical reactions occur, and it is the basis of transport and
lubricating fluids. It slowly absorbs and releases heat, thus helping to
maintain homeostatic body temperature, and it protects certain body
structures (e.g., the brain) by forming a watery cushion. Water is also a
reactant in hydrolysis reactions.
- Salts
in ionic form are involved in nerve transmission, muscle contraction,
blood clotting, transport of oxygen by hemoglobin, cell permeability,
metabolism, and many other reactions. Additionally, calcium salts (as
bone salts) contribute to bone hardness.
- Acids
are proton donors. When dissolved in water, they release hydrogen ions
(H+). Strong acids dissociate completely; weak acids dissociate
incompletely.
- Bases
are proton acceptors. The most important inorganic bases are hydroxides
(OH-). Bicarbonate ions are important bases in the body. When bases and
acids interact, neutralization occurs that is, a salt and water are
formed.
- pH
is a measure of the relative concentrations of hydrogen and hydroxyl ions
in various body fluids. Each change of one pH unit represents a 10-fold
change in hydrogen (or hydroxyl) ion concentration. A pH of 7 is neutral
(that is, the concentrations of hydrogen and hydroxyl ions are equal). A
pH below 7 is acidic; a pH above 7 is alkaline (basic).
- Normal
blood pH ranges from 7.35 to 7.45. Slight deviations outside this range
can be fatal.
- Organic compounds
- Organic
compounds are the carbon-containing compounds that living matter
comprises. Carbohydrates, lipids, proteins, and nucleic acids are
examples. They all contain carbon, oxygen, and hydrogen. Proteins and
nucleic acids also contain substantial amounts of nitrogen.
- Carbohydrates
contain carbon, hydrogen, and oxygen in the general relationship (CH2O)
their building blocks are monosaccharides. Monosaccharides include
glucose, fructose, galactose, deoxyribose, and ribose, disaccharides
include sucrose, maltose, and lactose; and polysaccharides include starch
and glycogen . Carbohydrates are ingested as sugars and starches.
Carbohydrates, and in particular glucose, are the major energy source for
the formation of ATP.
- Lipids
include the neutral fats or triglycerides (glycerol plus three fatty acid
chains), phospholipids, and steroids (most importantly, cholesterol).
Neutral fats are found primarily in adipose tissue, where they provide
insulation and reserve body fuel. Phospholipids and cholesterol are found
in all cell membranes. Cholesterol also forms the basis of certain
hormones, bile salts, and vitamin D. Like carbohydrates, the lipids are
degraded by hydrolysis and synthesized by dehydration synthesis.
- Proteins
are constructed from building blocks called amino acids; 20 common types
of amino acids are found in the body. Amino acid sequence determines the
proteins constructed. Fibrous, or structural, proteins are the basic
structural materials of the body. Globular proteins are functional
molecules; examples of these include enzymes, some hormones, and hemoglobin.
Disruption of the hydrogen bonds of functional proteins leads to their
denaturation and inactivation.
- Enzymes
increase the rates of chemical reactions by combining specifically with
the reactants and holding them in the proper position to interact. They
do not become part of the product. Many enzymes are produced in an
inactive form or are inactivated immediately after use.
- Nucleic
acids include deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). The
building unit of nucleic acids is the nucleotide; each nucleotide
consists of a nitrogenous base, a sugar (ribose or deoxy ribose), and a
phosphate group. DNA (the "stuff" of the genes) maintains
genetic heritage by replicating itself before cell division and contains
the code-specifying protein structure is a double-stranded helix. RNA
acts in protein synthesis to ensure that instructions of the DNA are
executed and is single-stranded.
- ATP
(adenosine triphosphate) is the universal energy compound used by all
cells of the body. When energy is liberated by the oxidation of glucose,
some of that energy is captured in the high-energy phosphate bonds of ATP
molecules and is stored for later use.
CHAPTER III
TISSUES
FIVE MAIN
TYPES OF TISSUES
1. BLOOD
AND LYMPH
-
Characterized
by having cells dispersed within a fluid.
The
fluid phase is called plasma.
BLOOD
Cells in Blood
·
Red
Cells / Erythrocytes
-
Have
no nucleus.
-
Contains
the oxygen-binding protein hemoglobin and their chief function is to transport
oxygen from the lungs to the tissues and return the carbon dioxide generated by
the cells to the lungs.
·
White
Blood cells / Leukocyte
-
Plays
a major role in the defense against infection.
Types:
-
Granulocytes
(basophils, eosinophils and neutrophils)
-
Monocytes
-
Lymphocytes
Blood also
contains small cell fragments known as Platelets.
Platelets – play crucial role in blood clotting.
LYMPH
-
A
clear fluid formed in the tissues.
-
It
contains many fewer cells than blood and its main cells are lymphocytes.
v
Blood and lymph are specialized tissue
that is characterized by having cells dispersed within a fluid medium.
2. CONNECTIVE
TISSUE
-
It
provides structural support to the various organs of the body.
-
They
are sometimes called structural tissues.
-
Main Cells
of Connective Tissue
·
Fibroblasts
-
Synthesize
and secrete the extracellular matrix (often called ground substance) and the
fibers that provide the mechanical strength of the connective tissues.
Extracellular
matrix consists of polysaccharides known as glycosaminoglycans.
Fat cells
are also called adipocytes.
Elastin – provide the elasticity that allows
tissues to resume their original shape after they have been stretched.
Elastin
fibers are found in the skin, lungs and in the walls of elastic arteries.
Two main
forms of Fatty Tissues
1. White
Adipose Tissue
-
Widely
dispersed throughout the body and forms its main energy reserve.
2. Brown
Adipose Tissue / Brown Fat
-
Important
in neonates, where it plays an important role in the maintenance of body
temperature.
3. NERVOUS
TISSUE
Two main
types of Cells in the CNS
1. Nerve
cells / Neurons
-
Provide
rapid and discrete signaling over long distances.
-
Has
extensive set of fine branches called dendrites.
Dendrites – receive information from other
neurons, integrate it and transmit it to its target cells in delicate extension
of the cell body called axon.
2. Glial
cells
-
Have
a complex supporting role.
Neutropil – the space between the nerve cell
bodies.
-
It
contains the cytoplasmic extensions of both neurons and glia.
v
Nervous tissue consists mainly of
neurons and glial cells.
v
It is found mainly in the brain and
spinal cord, but small ganglia are scattered throughout the body.
v
Nerve trunks connect the CNS to the
various organ systems.
4.
MUSCLE
TISSUE
-
characterized by its ability to
contract in response to an appropriate stimulus.
-
also known as myocytes.
Three main
types of Muscle
1. Skeletal
Muscle / Striated Muscles
-
A
muscle directly attached to the bones of the skeleton
2. Cardiac
Muscle / Striated Muscles
-
Muscle
of the heart.
3. Smooth
Muscles
-
Muscle
that lines the blood vessels and the hollow organs of the body.
Fascicles – layers of delicate connective tissue
that bind them together into bundles between the muscle cells.
5.
EPITHELIA
- A
continuous sheets of cells.
Vascular Endothelium - cell layer that lines the blood
vessels.
Mesothelium - the epithelial coverings of the
pericardium, pleura and peritoneal cavity.
Features
of Epithelia
Ø
They
are composed of cells that are tightly joined together via specialized
cell–cell junctions to form a continuous sheet.
Ø
Epithelial
cells lie on a matrix of connective tissue fibers called the basement
membrane. The basement membrane provides physical support and separates the
epithelium from the underlying vascular connective tissue, which is known as
the lamina propria.
Ø
Replace
damaged and dead cells, all epithelia undergo continuous cell replacement. The
rate of replacement depends on the physiological role of the epithelium and is
highest in the skin and gut, both of which are continually subjected to
abrasive forces.
Ø
The
arrangement of cells into epithelial sheets permits the directional transport
of materials either into or out of a compartment. In the gut, kidney and many
glandular tissues, this feature of epithelia is of great functional
significance. The surface of an epithelial layer that is oriented towards the
central space of a gland or hollow organ is known as the apical surface. The surface that is oriented towards the basement
membrane and the interior of the body is called the basolateral surface.
Classification
of Epithelia
·
Simple Epithelia
-
Consists
of a single cell layers and are classified according to the shape of the
constituent cell type.
·
Stratified Epithelia
-
Classified
according to the appearance of their constituent cells.
-
Characterized
by having more than one cell layer.
·
Pseudostratified Epithelia
-
Consists
of single layer of cells in contact with the basement membrane, but the varying
height and shape of the constituent cells gives the appearance of more than one
cell layer.
Ø
Simple squamous epithelium (squamous = flattened) consists of thin and flattened
cells. These epithelia are adapted for the exchange of small molecules between
the separated compartments. The walls of the alveoli of the lungs and the
endothelium of the blood vessels are squamous epithelia.
Ø
Simple cuboidal epithelium, as the name implies, consists of a
single layer of cuboidal cells whose width is approximately equal to their
height. A simple cuboidal epithelium forms the walls of the small collecting
ducts of the kidneys.
Ø
Simple columnar epithelium is adapted to perform secretory or
absorptive functions. In this form of epithelium, the height of the cells is
much greater than their width. It occurs in the large-diameter collecting ducts
of the kidneys. It is also found lining the small intestine.
Ø
Ciliated epithelium consists of cells that have cilia on
their apical surface. Non-ciliated cells are also interspersed between the
ciliated cells. Ciliated epithelia line the Fallopian tubes.
Ø
Pseudostratified columnar ciliated
epithelium
consists of cells of differing shapes
and height. This type of epithelium
predominates in the upper airways (trachea and bronchi).
Ø
Stratified squamous epithelium is adapted to withstand chemical and
physical stresses. The best-known stratified epithelium is the epidermis of the
skin. In this case, the flattened epithelial cells form many layers, only the
lowest layer being in direct contact with the basement membrane. The more
superficial cells are filled with a special protein called keratin, which renders
the skin almost impervious to water and provides an effective barrier against
invading organisms such as bacteria.
Ø
Transitional
epithelium is found in the bladder and ureters. It is similar in structure to
stratified squamous epithelium except that the superficial cells are larger and
rounded. This adaptation allows stretching of the epithelial layer as the
bladder fills.
v
Epithelia
are formed entirely from sheets of cells and consist of one or more cell
layers.
v
They
separate one compartment of the body from another.
v
An epithelium consisting of a single cell
layer is known as a simple epithelium while those with more than one layer are
called stratified epithelia.
Glandular Epithelia
-
Specialized
for secretion.
Exocrine Gland – a gland that secrete material via a
specialized duct onto an epithelial surface.
v
Glandular
epithelia are specialized for secretion.
v
If their secretion is via a duct, they form
part of an exocrine gland.
v
If their secretion passes directly into the
blood, they form part of an endocrine gland.
CELLS
v
For
cells to assemble into tissues, they need to adhere to other cells of the
correct type. This recognition requires tissue-specific cell-surface marker
molecules.
v
Cell–cell
adhesion and cell–matrix interactions play an important role in tissue
maintenance and development.
Specialized Cell Attachments
Junctional complex
- Consists of three structural components: the tight junction (also known as the zonula occludens), the adherens junction (or zonula adherens) and the desmosomes.
Gap junctions
- Allow small molecules to diffuse between adjacent cells.
In this way, they play a role in communication between neighbouring cells.
Claudins
– a transmembrane proteins that is responsible
for linking the epithelial cells so closely together.
Cadherins
– a
transmembrane adhesion protein which bind neighbouring cells together.
Hemidesmosomes
- they are formed by different anchoring proteins that bind
cytoskeletal intermediate filaments to transmembrane adhesion proteins known as integrins.
Integrins
- fix the epithelial cells to the basal lamina, so linking
the cell layer to the underlying connective tissue.
- play an
important role in development and wound repair.
Selectins
- a family of
adhesion molecules that mediates the initial attachment of a white blood cell
to the wall of a blood vessel before it can migrate to a site of tissue injury.
CHAPTER IV
INTEGUMENTARY SYSTEM
Ø
Forms
a covering for the body.
Ø
The skin is the largest organ in the body.
Ø
It consist the 12-15% of body weight with 1-2 meters surface area.
Ø
Multiple roles
in homeostasis, including protection, temperature regulation, sensory
reception, biochemical synthesis, and absorption.
Functions of the Skin
1.
Forms a protective covering to prevent injury or destruction
of underlying tissues from:
-
Entrance
of microorganisms
-
Harmful
chemiclas, acids, alkalies
-
Sun’s
rays
-
Extreme
of temperature
2.
Skin
excretes water and some waste products.
3.
Skin
helps to regulate body temperature by the evaporation of sweat and by dilation
of capillary blood vessels of the skin radiating heat.
4.
Skin
contains receptors of sensory nerves that pick up, and transmit it to the
brain, sensations of the external environment such as cold, heat, pain, touch
and pressure.
LAYERS OF THE SKIN
1. EPIDERMIS
-
The outer layer of the skin.
-
Consists of epithelial membrane.
-
It compromise of
five separate layers of epithelial tissue.
·
Stratum Corneum / Horny / Outer Layer
-
Outermost
layer of the epidermis.
-
Composed
of several thicknesses of degenerated cells that have become mere scales with
no cellular structure.
-
The
scales consist of a protein, keratin, the result of cellular degeneration
similar to that in the hair, nail, hoofs of animal, etc.
-
The
cells here are completely keratinized and dead, and this is what gives the skin
its waterproof quality.
·
Stratum Lucidum / Translucent / Clear
Layer
-
Lies
immediately under the horny layer, and consists of tiers of cells that have
lost their nuclei and cellular outlines due to the degenerative process.
·
Stratum Granulosum / Granular Layer
-
Lies
beneath the clear layer and is composed of two or three tiers of flattened
cells containing granules. There granules represent an early stage of
degeneration.
·
Stratum Spinosum / Prickel Cell Layer
-
Consists
of several tiers of many-sided cells. These are alive and represent mature
germinal cells.
·
Stratum Germinativum / Germinal /
Basal Layer
-
Consists
of a layer of columnar cells that forms the deepest part of the epidermis.
These cells contain a pigment that determines the darkness of the skin.
2. DERMIS
/ CORIUM / TRUE SKIN
-
Lies
under the epidermis.
-
Composed
of loose (areolar) connective tissue with widely separated cells, with fibrous
bands and elastic tissue fibers between.
-
The
dermis is formed from mesoderm, the middle layer of the embryo.
-
Have
a two layers / strata
·
Papillary Layer
-
Lies
next to the epidermis.
-
Its
outer surface is elevated into tiny projections with hollows between them.
·
Reticular Layer
-
Lies
beneath the papillary layer.
-
The
cells and fibers form an interlacing network.
-
Blood
vessels and nerves pass through this layer to reach the papillary layer.
NAILS
-
Nails
are form of epidermis that has benn modified by becoming keratinized.
-
The
stratum lucidum, the clear layer, has thickened to form a hard protective
covering for the tips of the fingers and toes.
-
Consists
of a nail root body and a free edge.
Functions of the Nail
1.
Protection
of the distal phalanx, the fingertip, and the surrounding soft tissues from
injuries.
2.
Enhace
precise delicate movements of the distal digits through counter-pressure
exerted on the pulp of the fingers.
3.
Acts
as a counterforce when the end of the fingers touches an object, thereby
enhancing the sensitivity of the fingertip.
4.
Function
as a tool, enabling for instance a so called “extended precision grip”.
·
Nail Root
-
The
proximal part that is covered by a fold of skin, and hidden from view.
·
Body of the Nail
-
This
is the exposed part, with its free edge projecting over the tip of the digit.
-
The
lunula is the white part of the nail body, shaped like a half-moon close to the
nail root.
·
Eponychium
-
The
outer horny layer of epidermis at the base of the nail that tends to grow out
over the nail body.
HAIR
-
A
modification of the epidermis.
-
Consists
of a hair root, a shaft and a hair sheath or hair follicle.
Functions of the Hair
1.
Provides
thermal regulation.
2.
Head hair protects the scalp against
the burning sun and helps hold in body heat.
3.
Eyelashes and eyebrow hair help keep
foreign matter out of the eyes.
4.
Hair in the nostrils and ear canal
help catch dust, debris and even insects from entering the body. Nostril hair
also helps regulate the temperature of inhaled air before it enters the body.
5.
Human body hairs are connected to
touch receptors in the skin that allow us to feel and, in that sense,
collectively serve as a protective warning device.
6.
Hair also serves the aesthetic
function of adding beauty to the human body.
7.
Facial hair helps differentiate men
from women, and pubic hair indicates that a man or woman has reached puberty
and is becoming sexually mature and ready to reproduce.
·
Hair
Follicle
-
Small canal opening upon the skin
surface and extending down into the dermis or even the subcutaneous tissue.
-
The hair follicle is the pore on the
scalp from which a hair grows.
·
Root
-
The part below the skin level lying
in a hair follicle.
·
Bulb
-
The inner enlarged end of each hair
root.
SEBACEOUS
GLANDS
-
Contains
a hair follicle and a hair. These units are found everywhere on the body except
on the palms, soles, top of the feet, and the lower lip.
-
Sebaceous
glands produce a substance called sebum, which is responsible for keeping the
skin and hair moisturized. During adolescence, sebaceous glands enlarge and
produce more sebum under the influence of hormones called androgens. After about age 20, sebum production begins to decrease.
-
If
the sebaceous gland does not produce enough sebum, the skin is dry. On the
other hand, if it produces too much sebum the skin is oily, a condition called
seborrhea. If sebum gets trapped in the pore, acne can develop.
SWEAT OR SUDORIFEROUS GLANDS
-
Simple tubelike glands consisting of
a single canal or duct, and a coiled secreting part.
-
Sweat
glands are tubes in which sweat is produced and
then transported to the surface of the skin.
-
Sweat
serves to cool the body off. To perform this purpose well, sweat glands are spread all over the body, with the
exception of places like the lips, parts of the genitals, and a person’s
nipples. In all, each person typically has more than two million sweat glands.
Two Types of Sweat Glands
-
The
most prevalent type of sweat glands. They are
located all over the body, especially in a person’s forehead, neck, back,
palms, and feet. These glands produce sweat when
a person becomes hot because of external heat, fever, exercise, and even
emotional upset. The sweat glands in the palms
and soles of the feet are particularly likely to react in stressful situations.
-
These
glands end in hair follicles.
-
They
are usually concentrated in areas that have hair, such as the armpits, around
the anus, and the external genital areas. These sweat
glands respond mostly to emotional stress of some type and also produce sweat when a person is upset or sexually excited.
-
Responsible
for much of a person’s body odor after forgetting deodorant or following
intense exercise. This is because the secretions from these glands have a
scent. In fact, apocrine glands are sometimes referred to as scent glands.
CERUMINOUS GLANDS
-
Are modified sweat glands located in
the external ear that secretes wax into the external acoustic (auditory)
meatus.
-
Are
simple, coiled, tubular glands made up of an inner secretory layer of cells and
an outer myoepithelial layer of cells
-
Cerumen
keeps the eardrum pliable, lubricates and cleans the external
auditory canal,
waterproofs the canal, kills bacteria, and serves as a barrier to trap foreign
particles (dust, fungal spores, etc.) by coating the guard hairs of the ear,
making them sticky.
SUBCUTANEOUS TISSUE / HYPODERMIS
-
Consisting of areolar (loose connective
tissue) forms a layer between the skin and such structures as muscles, bones,
or organs that lie deep to the skin.
-
The
third layers of skin.
-
Contains
fat and connective tissue that houses larger blood vessels and nerves. This
layer is important is the regulation of temperature of the skin itself and the
body. The size of this layer varies throughout the body and from person to
person.
-
Responsible
for regulating body temperature. A human’s subcutaneous
tissue also protects her inner organs and bones.
SECRETING
GLANDS
·
Endocrine
Glands / Ductless Glands
-
Have no ducts.
-
They discharged their secretions
directly into blood or lymph capillaries for distribution by the blood to all
body tissues. Their secretions are called hormones.
·
Exocrine
Glands
-
Have a secreting part and a duct.
-
The duct is a small canal through
which the secretion passes into a cavity, a hollow organ, or the skin surface.
-
The duct is formed by a single layer
of epithelial cells arranged to form a hollow tube.
Classification
of Exocrine Glands
1.
Simple
Tubular Gland
-
A single tube of cuboid cells, the
inner end of which forms a secretion that discharged through a single tube.
2.
Branched
Tubular Gland
-
A single duct with branches, with a
secreting part t the end of each branch.
3.
Simple
Saccular / Alveolar Gland
-
A sinle duct at the blind end of
which a saclike secreting part is located.
4.
Branched
Saccular
-
A single collecting duct with
branches opening into it, each branch ending in a saclike secreting end.
5.
Combined
Tubuloalveolar Gland
-
With tubular and sacular parts.
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