animal responses Flashcards
what are the two subdivisions of the human nervous system
central nervous system (CNS) - includes brain and spinal chord
and Peripheral nervous system (PNS) - includes all neurones that lie outside the CNS
what are most neurones within the CNS
relay/ intermediate neurons
how are the PNS’s axons and dendrons arranged?
in bundles / nerves
what is the autonomic nervous system responsible for?
- many homeostatic mechanisms
- controlling heightened responses (stress response)
what are nerves?
bundles containing the PNS’s axons and dendrons
what are features of autonomic neurones
- non-myelinated
- connections to effectors - consists of TWO neurones (in series)
- two neurones connected at a swelling (ganglion)
sympathetic and parasympathetic
effectors:
smooth muscle
cardiac muscle
exocrine glands
what are features of somatic neurones
myelinated
connections to effectors - consist of ONE neurone
effectors:
- voluntary/ skeletal muscle
what is the structure of sympathetic nervous system
many nerves
pre-ganglionic axons SHORT
ganglion - just outside nervous system
post-ganglionic axons LONG
what is the structure of the parasympathetic nervous system
pre-ganglionic axons - very long
ganglion - on the organ
post-ganglionic axons - very short
what is the function of the parasympathetic nervous system
return the body to rest
“rest and digest”
sympathetic nervous system
prepares the body for action
“fight or flight”
what are some examples of the effects of the sympathetic NS
- increased heart rate
- pupil dilation
- increased ventilation rate
what are some examples of the effects of the parasympathetic NS
- decreased heart rate
- pupil dilation
- decreased ventilation rate
what does the cerebrum do
all higher order processes
- thinking
- planning
- language
- memory
- emotions
what does the hypothalamus control
- control of the autonomic nervous system
- control of some endocrine glands
what are the main features of the cerebrum
- largest part of the human brain
- divided into cerebral hemispheres (right and left)
2 hemispheres are linked by the corpus callosum (white matter) - highly developed in humans
outer layer = cerebral cortex (grey matter)
what does the medulla oblongata control?
control of breathing
heart rate
smooth muscle
what does the medulla oblongata contain
- respiration centre
- cardiac centre
how does the hypothalamus bring about responses
- through the autonomic nervous system
- through controlling secretions of the pituitary gland
what are features of reflex actions
- do not involve any processing
- short nervous pathway
- two/three neurones - sensory, motor and sometimes relay
- brain may be involved after action has happened
- survival value
- danger
describe the knee jerk reflex
- spinal reflex - passes through the spinal chord
- only two neurones involved (sensory and motor)
- no relay so can’t be inhibited
- quicker helps with coordinated movement and balance
what physiological changes might occur during a fight or flight response
- blood pressure increases
- vasodilation
- increased blood glucose concentration (more glycogenolysis)
how are fight or flight responses coordinated
by the hypothalamus
- activates sympathetic NS - activates adrenal medulla
- secretion of adrenaline into blood stream
and
sympathetic nervous system
impulses activate glands and smooth muscles
and
hypothalamus
- secretes releasing hormones to stimulate pituitary gland
CRH - pituitary secretes ACTH - adrenal cortex secretes corticoid hormones
TRH - pituitary secretes TSH - thyroid gland secretes thyroxine
how does the heart adapt to supply more O2 and glucose and remove CO2
- increased heart rate
- increased stroke volume
- increased strength of contractions
