Animal responses Flashcards
sympathetic nervous system
many nerves out CNS leading to separate effectors ganglia just outside CNS short pre-ganglionic neurones long post-ganglionic neurones noradrenaline as neurotransmitter
parasympathetic nervous system
few nerves out CNS, divide and lead to diff effectors ganglia in effector tissue long pre-ganglionic neurones short post-ganglionic neurones acetylcholine as neurotransmitter
cerebrum
higher mental processes conscious thought memory actions emotional responses decisions reasoning
cerebellum
movement - contraction of skeletal muscles
balance/maintain body position
judge position of objects/limbs
hypothalamus
homeostatic responses
controls physiological processes
medulla oblongata
controls autonomic responses
association areas
compare sensory input with previous experience and judge appropriate response
pituitary gland
acts with hypothalamus
posterior lobe linked to hypothalamus by specialised neurosecretory cells (hormones made in hypothalamus pass down this to be released to blood from pituitary gland)
anterior lobe produces hormones released in blood in response to releasing factors from hypothalamus
medulla oblongata
controls non-skeletal muscles
cardiac centre regulates heart rate
vasomotor centre regulates circulation/blood pressure
respiratory centre regulates rate/depth of breathing
cranial reflex
passes through part of the brain but doesn’t involve thought processes in higher parts of the brain
corneal reflex
sensory neurone in cornea, AP enters myelinated neurones in pons
AP to sensory region in cerebral cortex to inform higher centres of brain and allow reflex to be overridden by conscious control (inhibitory signal to motor centre in pons)
how can an inhibitory AP prevent AP in motor neurone in corneal reflex?
myelinated neurones from/to cerebral cortex more rapid than non-myelinated relay neurone in pons
when activity is increased in sympathetic NS, where are hormones released from?
anterior pituitary gland
process of adrenaline taking effect
adrenaline binds to receptors on plasma membrane associated with G protein
G protein activated which activates adenyl cyclase
adenyl cyclase catalyses ATP to cyclic AMP (cAMP) which acts as the secondary messenger causing enzyme action
hormones form the anterior pituitary gland
hypothalamus secretes releasing factors (enzymes) which pass down portal vessel to pituitary
stimulate release of tropic hormones from anterior part which stimulate endocrine gland activity
corticotropin-releasing hormone (CRH) from hypothalamus
causes adrenocorticotropic hormone (ACTH) to be released and stimulates adrenal cortex to release corticosteroid hormones
thyrotropin-releasing hormone (TRH)
releases thyroid-stimulating hormone (TSH)
stimulates thyroid gland to release thyroid hormones
acts on nearly every body cell to increase metabolic rate and make cells more sensitive to adrenaline
atrial muscles have a higher _________ ______ than ventricle muscles
myogenic rate
frequency of heart contractions altered by….
cardiovascular centre in medulla oblongata
how does the medulla oblongata change frequency of contractions?
AP sent down accelerans nerve (sympathetic)
causes release of noradrenaline at SAN
increases heart rate
AP down vagus nerve
release acetylcholine so reduce heart rate
what monitors pH of the blood?
chemoreceptors in
carotid arteries
aorta
brain
what monitors blood pressure?
stretch receptors in walls of carotid sinus (small swelling in carotid artery)
cardiac muscle branches to form….
because….
cells in cardiac muscles joined by…
appears…….
cross-bridges
ensure AP spread evenly over walls
intercalated discs (cell surface membrane fused to produce gap junctions to allow diffusion of ions)
striated under microscope
skeletal muscle fibre surround by….
contents of fibres arranged into…
which are divided into chain of subunits called…
sarcolemma (membrane)
myofibrils (contractile elements)
sarcomeres
sarcomere
contain actin and myosin
stimulation of contraction
AP at end of axon
open Ca channels, Ca in, cause vesicles containing acetylcholine to fuse with membrane releasing across junction, fuse with receptors in sarcolemma
cause Na channels open, ions in muscle fibre
depolarisation of sarcolemma, down transverse tubules to muscle fibres
actin
2 chains twisted around each other
tropomyosin around actin
troponin (3 polypeptide chains) attached to tropomyosin, actin and calcium ions
maintaining ATP
aerobic respiration in mitochondria
anaerobic respiration in sarcoplasm
creatine phosphate (stores phosphates so can add to ADP)
