26-02-2016, 03:06 PM
Two Marks Q & A
1.Define cell
A cell is the basic living unit of the body.
2.The entire body contains above 100 trillion cells .
3.) What is a tissue?
A group of cells of the same type is called tissue.
4. How energy is released for cell function?
In all cells, oxygen combines with carbohydrate, fat or protein to release the energy required for cell function.
5. Discuss briefly about cell
Each cell consists of a centrally located nucleus (cell core) surrounded by the cytoplasm (cell body). The nucleus is separated from the cytoplasm by a nuclear
membrane.
6. About 75 percent of cell is water
7. The principle fluid medium of the cell is water .
8. What is protoplasm?
Different substances that make up the cell are collectively called protoplasm. It consists of water, electrolytes, proteins, lipids and carbohydrates.
9. The mitochondria organelles are called power houses of the cell
10. What is DNA?
DNA is nothing but deoxyribonucleic acid (DNA) similar to that found in the nucleus. DNA is the basic substance of the nucleus that controls replication of the cell.
11. The structure which is present inside the nucleus is called nucleolus
12. What is ECF?
Extra cellular fluid (ECF) is the fluid which lies outside the cell membrane.
13. What is ICF?
Intra cellular fluid (ICF) is the fluid which lies inside the cell membrane.
14 What is active transport?
When a cell membrane moves molecules or ions uphill against a concentration gradient, then the process is known as active transport.
15. What is passive transport?
The transport of the substances through the cell membrane occurs by diffusion is called passive transport.
16. Define membrane potential
The diffusion and drift processes give rise to membrane potential. The various ions seek a balance between the inside and outside of the cell by diffusion and drift.
17. Give the approximate value of the resting potential for living cell. The approximate value of the resting potential for living cell is – 70mV.
18. What is the range of resting potential?
The resting potential ranges from -60 to -100nV.
19. List the characteristics of resting potential.
•The value of the resting potential is maintained as a constant until some kind of disturbance occurs.
•It is strongly depending on the temperature.
•Since the permabilities of the different cell types vary, the corresponding resting potentials vary.
20. When the cell is said to be polarized?
When the cell is in resting state, then it is said to be polarized.
21. Define depolarization
The process of changing from the resting potential state to the action potential state is called depolarization.
22. State all-or nothing law
Regardless of the method of excitation of cells or the intensity of the stimulus, which is assumed to greater than the threshold of stimulus. The action potential is always- the same for any given cell. This is known as all- or nothing law.
23. Define absolute refractory period
Absolute refractory period is the time duration of the cell non response to further stimuli. It is about 1 millisecond in nerve cell.
24. Define relative refractory period
Following the absolute refractory period there is a brief period of time during which another action potential can be triggered but a much stronger stimulation is required. This period is called relative refractory period.
25. Define conduction velocity
The rate at which an action potential moves down a fiber of a nerve cell or is propagated from cell to cell is called the propagation rate or conduction velocity.
26.Give the range of nerve conduction speed
The conduction velocity varies in nerves depending on the type and diameter of the fiber and is from 20 n/s to 140 m/s. But in heart muscle, it is very slower ranging from 0.2 to 0.4 m/s.
27. Define depolarization and repolarization
When the cell fires however, the outside of the cell becomes momentarily negative with respect to the interior. A short time later, the cell regains the normal state in which the inside is again negative with respect to outside. The discharging and recharging of the cell is known as depolarization and repolarization.
28. A long is called axon .
29. The nerve cell with its dendrites and fiber is called neuron .
30. A connection between two excitable cells, in the form of a contact surface between two neurons is called synapse .
31. Discuss briefly about organ
The organ of the body is composed of various tissues. The organ contains tissue that furnishes some mechanical strength and specialized tissue that gives a particular function. There are five sense organs of the body. They are eye, nose, ear, tongue and skin.
32. The skeleton consists of 206 bones.
33. The skeletal bone are completely enclosed by a membrane called periosteum .
34. At the top of the skeleton cranium skull is placed.
35. Define inspiration and expiration.
Breathing IN is called inspiration, and breathing OUT is called expiation.
36. The central nervous system is made up of brain and spinal cord.