Coordination of responses+controlling heart rate- animal responses Flashcards
2 main types of receptors
-electrical activity in response to stimuli
-secrete messenger chemicals e.g hormones
-these impulses or hormones travel to a coordinator-effector-response
coordination of nervous and endocrine system in fight or flight
-initial part caused by nervous system
1- sensory neurones detect stimuli associated with danger+send impulses to brain
2-amygdala (in cerebrum), sends impulses to other parts of brain, hypothalamus
3-hypthalamus sends impulses via sympathetic nerves to adrenal glands
4-adrenal medulla secretes adrenaline
-at same time, hypothalamus releases a peptide hormone which stimulates anterior pituitary gland to secrete ACTH, which travels to adrenal glands via bloodstream, = adrenal cortex secretes cortisol
role of cortisol
increase blood pressure and blood glucose and suppresses the immune system
effects of adrenaline
-increases diameter of bronchioles=more air flow
-pupils dilate
-higher blood pressure
-increases blood flowing to muscles and brain via vasodilation
-heart rate increase
-stimulates breakdown of glycogen into glucose
myogenic meaning
-does not require any external stimuli to contract e.g cardiac muscle
-rate of heart controlled by nervous and endocrine system
role of medulla
-controls heart rate
composition of medulla
-made up of an acceleratory centre and an inhibitory centre
-both centres connected to sino atrial node
acceleratory centre
-once activated, impulse sent along sympathetic neurones to SAN
-noradrenaline secreted at synapse which cause SAN to increase the frequency of its electrical waves= increases heart rate
inhibitory centre
-once activated, impulses sent along parasympathetic neurones to SAN
-Acetylcholine secreted at synapse=reduce frequency of electrical waves it produces=decreases heart rate
