Question 3 : Using an example, describe possible changes in the body that might occur during homeostasis. (8 mark)
Homeostasis is maintained by control systems which detect and respond to changes in the internal environment. A control system has three basic component which is detector, control centre and effector.
- For example control of body temperature:
- When body fall below the preset level, its detected by by specialised temperature sensitive nerve ending (detector).
- They transmit the informations as an input to group of cell in the hpothalamus of the brain which form the control centre
- The output from the control centre activates mechanisms that raise body temperature (effectors). These include stimulation of skeletal muscle causing shivering, narrowing of blood vessels in the skin reducing the blood flow to and heat loss from the peripheries and behavioural change example put on more clothes or curl up.
Question 4 : Discuss the role of negative feedback and positive feedback in maintaining homeostasis. (5m)
Negative feedback mechanism
Positive feedback mechanism
Question 5: How would a Respiratoy system disease affect the Cardiovasular system? (7m)
The blood circulatory system, also called the cardiovascular system, consists of the heart and the blood vessels that run throughout the body. It delivers nutrients and oxygen to all cells of the body.
The oxygen we breathe gets mixed into the blood in the lungs, and the heart pumps this blood to all parts of the body. Each heartbeat is a contraction of the heart as it pumps blood around the body.
The heart has four chambers: the left atrium, right atrium, right ventricle and left ventricle. They are all separated by one-way valves, meaning the blood can only flow in one direction. Blood is carried to the heart in the veins, and back out to the rest of the body in the arteries.
Disease in other organ systems, particularly in lungs can cause heart failure. Obstructive changes in the lungs result in increased pulmonary vascular resistance, which increase the Right Ventricle workload. In time, the right side of the heart has difficulty pumping blood forward to the lungs, becomes dilated, and hypertrophies. Then signs and symptoms of right side heart failure are seen. Cor Pulmonale is the term for Heart Failure resulting from obstructive lung disease such as cystic fibrosis or bronchopulmonary dypslasia
Question 6 : Define Sural, Pollex, Occipital, Manus, Popliteal, Sacral, pedal, metal, antecubital and Hallux. (6 m)
the calf of the leg
the innermost digit of the forelimb; thumb
the distal segment of the forelimb of a vertebrate, including the carpus and the forefoot or hand
relating to the ham, or part of the leg back of the knee
relating to the sacrum
relating to a foot or the feet.
relating to the chin
In front of the elbow
the first or innermost digit of the foot of humans
Question 7: Differentiate between microfilament, intermediate filament and microtubule. (6m)
The smallest of the cytoskeletal elements.
The protein composition of intermediate filament varies among cell types
Insoluble and the most durable of cytoskeletal elements
Microtubules (hollow tube built from globular protein tubulin), the distribution in the cell change over the time.
Less the 6mm in diameter Composed of the protein ACTIN .
Range from 7-11mmin in diameter. Intermediate in size.
Diameter about 25nm, extens outward into the periphery of the cell from a region near the nucleus called the centrosome
3 major fuction:
3 major fuctions:
4 major fuctions:
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