General Physiology practice paper

Question 1

Explain how bone adaptations occurs using Wolff’s law of bone remodelling (6 marks)

Answer 1

• Bone adapts to loads under which it is placed
• During resorption the osteoclasts dominate and remove bone
• this happens when there is decreased stress
• bone becomes weaker
• during formation the osteoclasts dominate
• this happens when there is increase in load therefore bone becomes stronger

Question 2

Describe the process of exhalation (6 marks)

Answer 2

• diaphragm and intercostal muscles relax and the recoil of the diaphragm superiorly and the fall of the ribcage under gravity
• this decreases volume and increases pressure in the thorax
• air moves from its high pressure in the lungs to a low pressure in the atmosphere

Question 3

Name the three main bone cells involved in bone modelling and describe their function

Answer 3

• osteoblasts: bone formation
• osteoclasts: bone respiration
• osteocytes: sense mechanical strain

Question 4

5 components of the cardiovascular system

Answer 4

heart, arteries, capillaries, veins and blood

Question 5

definition of systolic blood pressure

Answer 5

resistance of blood in the arteries when the ventricles contract

Question 6

describe what happens in the first phase of the cardiac cycle

Answer 6

• blood returns via the vena cava and pulmonary veins and enters the atria.
• ventricles are relaxed so the AV valves open and blood flows into the ventricles which start to fill diastolic ally.

Question 7

name the organelle which produces ATP

Answer 7

mitochondria

Question 8

name the mechanism by which the action potential stimulates skeletal muscle to contract

Answer 8

excitation contraction coupling

Question 9

describe the similarities and differences between simple diffusion and osmosis

Answer 9

similarities: both move molecules from a high concentration to a low concentration, both examples of passive transport and both go down a concentration gradient

differences: osmosis needs a semi-permeable membrane and relies on the movement of water

Question 10

list the 4 phases of the healing response

Answer 10

haemostasis, inflammation, proliferation, maturation

Question 11

definition of a tissue

Answer 11

group of similar cells that have a common function

Question 12

name the type of mechanoreceptors that derive information from blood pressure

Answer 12

baroreceptors

Question 13

4 properties of the alveoli that make them adapted to gas exchange

Answer 13

• large surface arra
• extensive blood supply
• thin walled cells
• short diffusion distance

Question 14

name one function of the skeleton and describe how it achieves this function

Answer 14

protection- it protects vital organs such as the skull protects the brain

Question 15

describe how rising CO2 in blood stimulates leads to an increase in the rate and depth of breathing

Answer 15

• increased co2 stimulates chemoreceptors located in the aorta and carotid arteries and within the medulla oblongata
• this sends increased frequency waves to the dorsal respiratory group which is a respiratory centre of the medulla oblongata.
• this ordinates chemoreceptors and higher brain inputs. This would increase stimulation from ventral respiratory groups

Question 16

describe the neural regulation of blood pressure when there is a drop in pressure

Answer 16

• baroreceptors are found in the aorta and carotid arteries.
• a drop in pressure would reduce the stretch and frequency of nerve impulses to the CV centre of the medulla oblongata
• the cardiac centre of the CV centre would increase HR by reducing the parasympathetic output

Question 17

identify which fibres are the most dominant in tendons and describe how this affects their function

Answer 17

collagen fibres, they have high tensile strength which allows tendons to be resistant to stretch

Question 18

name one disease of the skeletal system

Answer 18

osteoarthritis