Question

define/ explain the following terms:

1-simple vs stratified eqithelium

2- smooth muscle vs skeletal muscle

3- extracellular matrix

4-axon vs dendrites

5- lacunae in cartilage and hard bone

6- erythrocytes, leukocytes and thrombocytes

Answer 1

1- simple epithelium(SE) is made up single layer of the cell directly attached to the collagen layer. SE is mainly found on those places where absorption and filtration is more frequent. SE is of 4 types. A- simple squamous B-simple quboidal. C- simple columnar. D- pseudo stratified.

Stratified epithelium is made up of multiple layers where only one layer attached to Basel membrane and others adhere to each other to maintain structural intigrity. Stratified epithelium is quite thick making it unsuitable for absorption and filtration thus the main function is protection. This is also of 4 types- squamous, cuboidal, columnar and transitional.

2-Smooth muscle(SM) are non striated muscle that are not under control of voluntary action.These are generally present in uterus, trachea, stomach and other hollow organs.Most of SM r of single unit that is either whole muscle will contract or relaxes but there are multi unit SM in trachea.

Skeletal muscles are the striated muscle that is under voluntary control of the somatic nervous system of the brain.These muscle are connected to the bone by tendon. Main function include support and movement.

3-Extracellular matrix (ECM) is the non cellular component present with in the all tissues and organ and composed of water, protein and polysaccharides and each tissue have different ecm in terms of composition that has been developed through the complex developmental processes.Have many cell adhesion molecules like integrin an s responsible for many vital processes.

4- axons are the long fibrous projection that conduct electrical impulses away from the body. These are highly myelinated star. with intermittent demylinatiion ( node of ranveranveir), wrapping of schwan cell is responsible for mylination.Because of mylination the impulse is conducted in discontinuous way known as saltatory movement.

Dendtrites are the branched projection of the neuron and receive electrochemical signals from another neurons and transmit it to the cell body of a neuron from which they projects.

5-lacunae are the small spaces in cartilage and contains osteocytes. One lacunae contains only one osteocytes and are interconnected by small canal called canaliculy.Canaliculy work as transport channel to transfer the nutrient to osteocytes and carry back the waste.

Hard bone form by ossification and mineralization of cartilage various, proteins like ossien, minerals and cells like oateoblast and oateoblast participate in this process.

6-erythrocytes are the red blood corpuscells that does not have nucleus and contains haemoglobin that supplies oxygen to the body and carry co2 from organs to lungs.

Leukocytes are colorless body's immune system cells that circulate throughout the body and tackles the foreign materials like bacteria. Eosinophil, basophil, monocytes,neutrophils, t and b lymphocytes are major leukocytes. These are the cells responsible for fighting against various diseases and protects us from foreign invaders

Thrombocytes also known as platelets are the megakaryotes(very large cell) without nucleus whose main function is to prevent bleeding and thus to initiate blood clothing.