Response long questions

Question 1

transmission of nerve impulses across synapse

Answer 1

1. When nerve impulse reaches presynaptic membrane

synaptic vesicles triggered to release neurotransmitters into the synaptic cleft

2. neurotransmitter diffuse across synapse to bind to the receptor proteins
3. generation of new electrical signals in postsynaptic membrane

Question 2

Reflex action (knee-jerk reflex)

Answer 2

1. hit tendon that connects the quadriceps muscle in the thigh to a bone in lower leg

2.force stretches quadriceps muscles
stimulates stretch receptors in muscles
trigger nerve impulse

3. afferent neurone transmit information to efferent neurones in spinal cord
4. efferent neurone transmit information to quadriceps muscle
   muscle contract
   lower leg jerk forward

Question 3

effects of alcohol consumption

Answer 3

1. transmission of nerve impulses becomes slower
   (alcohol affects transmission of neurotransmitters across synapse)
2. coordination is affected

Question 4

patient suffering from diabetes mellitus

Answer 4

1. High intake of glucose
   cause excess glucose in blood
   cannot be fully reabsorbed from proximal convoluted tubule into blood capillaries
2. excess glucose is excreted in urine

Question 5

diet rich in proteins cause increase in urea content

Answer 5

1, proteins are digested to amino acids

2. excess amino acids cannot be stored in body
   must be deaminated in liver
3. the amino group from amino acids is converted to urea
4. urea is transported by blood to kidneys
   excreted in urine

Question 6

how reabsorption of sodium ions is controlled

Answer 6

1. when blood osmotic pressure decreases
   stimulate adrenal cortex to secrete aldosterone
2. cause distal convoluted tubule and collecting duct becomes more permeable to sodium ions

3, more sodium ions is reabsorbed into blood

Question 7

how athlete regulates blood osmotic pressure on hotday

Answer 7

1. athlete secrete sweat to lose heat
   increase blood osmotic pressure

2.hypothalamus stimulate pituitary glands to release more ADH into blood

3. high level of ADH increase the permeability of distal convoluted tubule and collecting duct
   more water is reabsorbed
4. blood osmotic pressure returns to normal