reflexes

Question 1

what is a reflex

Answer 1

rapid, involuntary response to an adverse stimulus, not involving any processing in the brain to cooridante movement

-

Question 2

what reflex is a knee-jerk reflex and how many and which neurones are involved

Answer 2

-spinal reflex
-only 2 neurones= sensory and motor

Question 3

how do
-pupils
-heart rate + blood pressure
change durng fight or flight and what is the survival value

Answer 3

-pupils dilate= more light enters retina, more sensitive, greater visual stimulus
-HR and BP increases= increase blood flow, deliver more oxygen and glucose to muscles for respiration, faster removal of co2 and toxins

Question 4

how do
-digestive system and skin arterioles
-muscle and liver arterioles
change during fight or flight and what is the survival value

Answer 4

1. constrict= diverts blood away from the skin and digestive system and towards the muscle
2. dilate= more blood delivering more o2 and glucose for respiration to muscles, more glycogen converted to glucose-glycogenolysis- in liver and transported via blood stream

Question 5

how do
-blood glucose levels
-metabolic rate
change during fight or flight and what is the survival value

Answer 5

1.increase= supplies substrate for respirator for muscle contraction
2.increases= converts glucose to useable forms of energy such as ATP

Question 6

how do
-erector pili muscles in skin
-ventilation rate and depth
change durng fight or flight and what is the survival value

Answer 6

1. contract= hairs stand up= sign of aggression
2. increase= increased gas exchange, more oxygen entering the blood for aerobic respiration

Question 7

how do
-endorphins
change durng fight or flight and what is the survival value

Answer 7

released in the brain= any wounds inflicted on the mammal do not prevent activity

Question 8

where can external and internal threats be detected

Answer 8

-by receptors in the eyes ears and nose
-internal detected by e.g a fall in blood pressure detected by baroreceptors in the carotid artery and aorta

Question 9

explain the coordination of the fight or flight response

Answer 9

1. sensory centres in cerebrum process these sensory inputs
2. signals are passed to the association centres
3. cerebrum stimulates hypothalamus if the threat is recognised
4. hypothalamus increases activity of the sympathetic nervous system stimulating release of hormones from the anterior pituitary gland

Question 10

what are the roles of hormones of the hypothalamus and anterior pituitary gland

Answer 10

Releasing hormones secreted by the hypothalamus pass down a portal vessel to the pituitary gland and stimulate the release of tropic hormones from the anterior pituitary

anterior pituitary gland releases ATCH causing adrenal cortex to release cortisol hormone= stimulates target organs and tissues inreasig blood pressure and blood glucose concentration
-Thyrotropin-releasing hormone (TRH) causes the release of thyroid-stimulating hormone (TSH) which stimulates the thyroid to stimulate more thyroxine…

Question 11

explain the mechanism of adrenalin

Answer 11

1. adrenalin (first messenger) binds to receptor
2. complimentary/ specific shape
3. G protein activated
4. adenyl cyclase activated
5. ATP converted to cAMP (secondary messenger)
   6.cAMP activates proteins/ enzymes
6. by altering 3D structure/ phosphorylation