Histology.
Ciliated Epithelium tissue :
Ciliated columnar epithelial cells are rectangular in shape and have between 200 to 300 hair-like protrusions called cilia.
The mitochondria are found toward the apical region of the cell while the cell nuclei are found towards the base and are often elongated.
Cells are interconnected via desmosomes and tight junctions, creating a semipermeable membrane that is more selective that membrane found in other types of cell.
Cuboidal Epithelium:
These are epithelial cells having a cube-like shape; that is, their width is approximately equal to their height.
They may exist in single layers (simple cuboidal epithelium) or multiple layers (stratified cuboidal epithelium) depending on their location (and thus function) in the body.
Stratified Columnar Epithelium :
Stratified columnar epithelia are found in the ocular conjunctiva of the eye, in parts of the pharynx and anus, the female's uterus, the male urethra and vas deferens.
The cells function in secretion and protection.
In simple terms, we can say that the upper and lowermost layer of cells are columnar in shape. The middle layer contains cuboidal cells.
It forms the lining of the respiratory tract, ureter, oviduct ,etc.
Stratified Cuboidal Epithelium:
Stratified cuboidal epithelium is a type of epithelial tissue composed of multiple layers of cube-shaped cells.
Only the most superficial layer is made up of cuboidal cells, and the other layers can be cells of other types.
This is because, conventionally, naming of stratified epithelium is based on the type of cell in the most superficial layer.
Areolar connective tissue:
Loose connective tissue is the most common type of connective tissue in vertebrates.
It holds organs in place and attaches epithelial tissue to other underlying tissues.
It also surrounds the blood vessels and nerves.
Cells called fibroblasts are widely dispersed in this tissue; they are irregular branching cells that secrete strong fibrous proteins and proteoglycans as an extracellular matrix.
The cells of this type of tissue are generally separated by quite some distance by a gelatinous substance primarily made up of collagenous and elastic fibers.
Hyaline cartilage:
Hyaline cartilage is covered externally by a fibrous membrane, called the perichondrium, except at the articular ends of bones and also where it is found directly under the skin, i.e. ears and nose.
This membrane contains vessels that provide the cartilage with nutrition.
Hyaline cartilage matrix is mostly made up of type II collagen and chondroitin sulfate, both of which are also found in elastic cartilage.
Hyaline cartilage exists on the ventral ends of ribs; in the larynx, trachea, and bronchi; and on the articular surface of bones.
Tendon:
A tendon (or sinew) is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension.
Tendons are similar to ligaments and fascia; all three are made of collagen.
Ligaments join one bone to another bone; fasciae connect muscles to other muscles.
Tendons and muscles work together to move bones.
Human Vein :
Veins (from the Latin vena) are blood vessels that carry blood toward the heart.
Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart.
In contrast to veins, arteries carry blood away from the heart.
Veins are less muscular than arteries and are often closer to the skin.
There are valves in most veins to prevent backflow.
Cardiac Muscle:
Cardiac muscle is involuntary, striated muscle that is found in the walls of the heart, specifically the myocardium.
Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
The cells that constitute cardiac muscle, called cardiomyocytes or myocardiocytes.
The myocardium is the muscle tissue of the heart, and forms a thick middle layer between the outer epicardium layer and the inner endocardium layer.
The cells are branched and are characterized by presence of intercalated discs which give them a striated appearance.
Smooth Muscle:
Smooth muscle is an involuntary non-striated muscle.
Cells are spindle-like in shape and contain a single nucleus.
Smooth muscle is found within the walls of blood vessels (such smooth muscle specifically being termed vascular smooth muscle) such as in the tunica media layer of large (aorta) and small arteries, arterioles and veins.
Smooth muscle is also found in lymphatic vessels, the urinary bladder, uterus (termed uterine smooth muscle), male and female reproductive tracts, gastrointestinal tract, respiratory tract, arrector pili of skin, the ciliary muscle, and iris of the eye.
Neuron:
Each nerve cell has following important parts;
Dendrites.
Cell Body.
Axon.
Axon terminal.
Dendrites are cell processes that carry impulses towards the cell, a neuron may have many dendrites.
Cell body is also called “Soma”, contains nucleus and regulates the functioning of neurons.
Axon is a long cell process that carries nerve impulses.
Axon terminals are endings of neurons where neurotransmitters are stored to be released in synapse.
Synapse is a minute space between two neurons, the impulse passes through synapse by means of chemicals called “Neurotransmitters”.
Some neurons containing a sheath of a fatty substance around the axon called ‘Myelin Sheath” are called as “Myelinated Neurons”.
The neurons which are not covered by Myelin sheath are called as ‘Non Myelinated Neurons”
Myelin sheath is covered by a type of glial cell called “Schwann Cell”.
The groove on the Myelinated neuron where myelin sheath is absent and axon is exposed is called the “Node of Ranvier”.
Adipose tissue:
It is a loose connective tissue composed mostly of adipocytes.
In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells (i.e., adipose tissue macrophages [ATMs]).
Adipose tissue is derived from preadipocytes.
Its main role is to store energy in the form of lipids, although it also cushions and insulates the body.
Far from hormonally inert, adipose tissue has, in recent years, been recognized as a major endocrine organ, as it produces hormones such as leptin, estrogen, resistin, and the cytokine TNFα.
Moreover, adipose tissue can affect other organ systems of the body and may lead to disease.
The two types of adipose tissue are white adipose tissue (WAT), which stores energy, and brown adipose tissue (BAT), which generates body heat.
