As
a beginner student in the field of medicine, honestly saying I don’t have any
idea that there are different types of cells, glands and membranes which are
part of the composition of our human body. But as time goes by, as the time I’ve
reached the age of 12 I think, I’ve some ideas about human body compositions.
And as I become a first year nursing student of SLCN. I’ve discover all of
these ideas which I will share here our blog. I hope that I could share my
knowledge to everyone who might have the chance to read this blog of ours.
These are the things that I’ve learned in the 2nd semester in Human
Anatomy and Physiology. How I wish I could be our professor in HAP, he is really
amazing. If you will have the chance to know him, I know you’ll surely agree
with me. Look what we’ve learned from him. So let’s start I hope you’ll enjoy
reading these blog, there are some pictures and videos shown. Sorry if there
are some grammars that are wrong, I’m that good in English. Then enjoy, and
thanks for visiting our blog! Looking forward for your good comments.
Embryonic
Tissue:
From the term
itself, an embryonic tissue is the tissue that can be found in an embryo. Endoderm and Ectoderm are the cells
that give rise to a new individual. The cells of ectoderm will migrate between
the two layers and the so called mesoderm
will be formed. Endoderm is the
inner layer; Ectoderm is the outer
layer and Mesoderm is the middle
layer. They are called the germ layers;
it is because they give rise to all the body tissues. There is a portion of the
ectoderm called Neuroectoderm (Nervous
System).
The Four known types of Tissues are:
1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Nervous Tissue
1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Nervous Tissue
1. Epithelial Tissue a layer of cells that serves as a protective covering over some surface,
such as the outside of an organ or the lining of the wall of a cavity in the
body. Epithelial cells generally have large nuclei, clear outlines, and a large
amount of granular protoplasm. Some, called columnar, are long and narrow and
may, as in the respiratory tract, have hairlike cilia extending from the outer
surface. The skin contains several layers of epithelial cells, with columnar cells at the bottom, squamous cells at the top, and cuboidal cells in middle layers. Many
of the secretory glands are composed of epithelial cells as are some of the
endocrine glands.
Functions of Epithelial Tissues:
1. Protecting underlying structures.
2. Acting as barriers.
3. Permitting the passage of substances.
4. Secreting substances.
5. Absorbing substances
2. Acting as barriers.
3. Permitting the passage of substances.
4. Secreting substances.
5. Absorbing substances
Structural Classifications of Epithelial Tissue:
 |
| Simple Squamous Structure: Single layer or flat, often hexagonal cells. Function: Diffusion, filtration and etc. Common Location: Lung alveoli |
 |
| Simple Cuboidal Structure: Single layer of cube-shaped cells. Fuction: Active transport and it facilitates diffusion. Common Location: Kidney Tubules |
 |
| Simple Columnar Structure: Single layer of tall, narrow cells. Function: Movement of particles out of the bronchioles of the lungs. Common Location: Lining stomach and Intestines |
 |
| Pseudostratified Structure: Single layer of cells, Some are tall and thin. Function: Synthesize and secretes mucus membrane. Common Location: Trachea and Bronchus |
 |
| Stratified Cuboidal Structure: Multiple layers of cube-shaped cells. Function: Absorption and protection against microorganisms. Common Location: Parotid gland duct |
 |
| Stratified Columnar Structure: Multiple layers of cells with tall and thin cells. Function: Protection and secretion. Common Location: Larynx |
 |
Transitional
Structure: Stratified cells that appear cuboidal when a certain organ isn't stretched.
Function: Accommodates fluctuations.
Common Location: Ureter, Urethra and Urinary bladder
|
2.
Connective Tissue which support and hold parts of the body together, comprise the fibrous
and elastic connective tissues, the adipose (fatty) tissues, and cartilage and
bone. In contrast to epithelium, the cells of these tissues are widely
separated from one another, with a large amount of intercellular substance
between them. The cells of fibrous tissue, found throughout the body, connect
to one another by an irregular network of strands, forming a soft, cushiony
layer that also supports blood vessels, nerves, and other organs. Adipose tissue
has a similar function, except that its fibroblasts also contain and store fat.
Elastic tissue, found in ligaments, the trachea, and the arterial walls,
stretches and contracts again with each pulse beat. In the human embryo, the
fibroblast cells that originally secreted collagen for the formation of fibrous
tissue later change to secrete a different form of protein called chondrion, for the formation of
cartilage; some cartilage later becomes calcified by the action of osteoblasts to form bones. Blood and
lymph are also often considered connective tissues.
Functions of a
Connective Tissue:
1. Enclosing and separating.
2. Connecting
3. Supporting and moving
4. Storing
5. Cushioning and insulating
6. Transporting
7. Protecting
7. Protecting
Structural classification of
Connective Tissue
 |
| Loose Connective Structure: Fine network of fibers. Function: Loose packing support and nourishment. Common Location: Skin |
 |
| Dense Regular Collagenous Structure: Matrix compose of collagen fibers Function: Great tensile strength and stretch resistance Common Location: Ligament and Tendon |
 |
| Dense Regular Elastic Structure: Regularly arranged collagen fibers and elastin fibers. Function: Stretching and recoiling Common Location: Tongue and Vestibular fold |
 |
| Dense Irregular Collagenous Structure: Alternating planes of fibers. Function: Tensile Strength Common Location: Skin |
 |
| Dense Irregular Elastic Structure: Bundles of sheets and elastin fibers Function: Strength and stretching Common Location: Aorta |
 |
| Adipose Structure: Full of lipid Function: Packing material, thermal insulator, etc. Common Location: Mammary gland |
 |
| Reticular Structure: Fine network of reticular fibers Function: Provides a superstructure for lymphatic and hemopoietic . Common Location: Lymph Node and Spleen |
 |
| Hyaline Cartilage Structure: Small and evenly dispersed. Function: Allows growth, provides rigidity. Common Location: Bone |
 |
| Fibrocartilage Structure: Thick bundles Function: Flexible and capable of withstanding pressure. Common Location: Intervertebral disk |
 |
| Elastic Cartilage Structure:Matrix contains elastic fibers. Function: Provides rigidity and flexibility. Common Location: Ears |
 |
| Bone Structure: Hard, bony matrix predominates. Function: Provides strength, support and protects. Common Location: Bones |
 |
| Blood Structure: Blood cells and a fluid matrix Function: Transports oxygen etc. Common Location: Red and white blood cells |
3.
Muscle Tissue
these tissues, which contract and relax, comprise
the striated, smooth, and cardiac muscles. Striated muscles, also called
skeletal or voluntary muscles, include those that are activated by the somatic,
or voluntary, nervous system. They are joined together without cell walls and
have several nuclei. The smooth, or involuntary muscles, which are activated by
the autonomic nervous system, are found in the internal organs and consist of
simple sheets of cells. Cardiac muscles, which have characteristics of both
striated and smooth muscles, are joined together in a vast network of
interlacing cells and muscle sheaths.
Structural Classification of Muscle Tissue
 |
| Skeletal Muscle |
This type of
muscle is composed of long fibers surrounded by a membranous sheath, the
sarcolemma. The fibers are elongated, sausage-shaped cells containing many
nuclei and clearly display longitudinal and cross striations. Skeletal muscle
is supplied with nerves from the central nervous system, and because it is
partly under conscious control, it is also called voluntary muscle. Most
skeletal muscle is attached to portions of the skeleton by connective-tissue
attachments called tendons. Contractions of skeletal muscle serve to move the
various bones and cartilages of the skeleton.
b.
Smooth Muscle
 |
| Smooth Muscle |
Visceral, or
involuntary, muscle is composed of spindle-shaped cells, each having a central
nucleus. The cells have no cross striations, although they do exhibit faint
longitudinal striations. Stimuli for the contractions of smooth muscles are
mediated by the autonomic nervous system. Smooth muscle is found in the skin,
internal organs, reproductive system, major blood vessels, and excretory
system.
c.
Cardiac Muscle
 |
| Cardiac Muscle |
This muscle
tissue composes most of the vertebrate heart. The cells, which show both
longitudinal and imperfect cross striations, differ from skeletal muscle
primarily in having centrally placed nuclei and in the branching and
interconnecting of fibers. Cardiac muscle is not under voluntary control. It is
supplied with nerves from the autonomic nervous system, but autonomic impulses
merely speed or slow its action and are not responsible for the continuous
rhythmic contraction characteristic of living cardiac muscle.
4.
Nervous Tissue these highly complex groups of cells, called ganglia, transfer
information from one part of the body to another. Each neuron, or nerve cell,
consists of a cell body with branching dendrites and one long fiber, or axon.
The dendrites connect one neuron to another; the axon transmits impulses to an
organ or collects impulses from a sensory organ.
 |
| Nerve cell Axon- is the transmitter. Dendrites - is the receiver. |
Gland - a gland is a secretory structure. There are two types of glands first is the endocrine glans which do not consist ducts and exocrine glands. Endocrine glands is the one responsible for secreting hormones, which enter the blood and are carried to other parts of the body. Exocrine glands, release their secretion into ducts which empty onto a surface or a cavity. Exocrine glands can also be classified according to how it products leave cell. Merocrine glands, are glands of the cell that produce secretions by active transport or produce vesicles that contain secretory products. Apocrine glands, it is the secretory products that are stored in the cell near the lumen of the duct. and the Holocrine gland it is the secretory products are stored in the cells of the gland.
 |
| Glands |
MEMBRANE
Membrane - is a thin sheet or layer of tissue that covers a structure or lines a cavity. Most membranes are formed from epithelium and the connective tissue on which it rests.There are three major categories of internal membranes are mucous membranes, serous membranes and synovial membranes. Mucous membranes, consist of various kinds of epithelium resting on a thick layer of loose connective tissue. Serous membranes, consists of simple squamous epithelium resting on a delicate layer of loose connective tissue. It doesn't contain glands but it do produces serous fluid. And Synovial membranes, consists of modified connective tissue of the joint cells, either intermixed with part of the dense connective tissue of the joint capsule. It produces synovial fluid, which lubricates the joint for smooth joint movement.
So these are all the things I've learned as we start our lesson in Human Anatomy and Physiology.
Thanks for visiting! Just leave your comments below. Enjoy reading our blog.
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