animal responses Flashcards
Describe the peripheral nervous system
Made up of neurons that connect CNS to the rest of the body
What is the somatic nervous system
Controls conscious activities like running
What is the autonomic nervous system
Controls unconscious activities like digestion
What is the sympathetic nervous system
Gets body ready for fight or flight response
Releases noradrenaline
What is the parasympathetic nervous system
Calms body down
Rest and digest system
Releases acetylcholine
Where is the hypothalamus located
Beneath the middle part of brain
Roles of hypothalamus
Maintains body temperature
Produces hormones that control pituitary gland
Where is the pituitary gland located
Beneath hypothalamus
Role of pituitary gland
Releases hormones and stimulates other glands like the adrenal gland
What is a reflex
The body responds to stimulus without making a conscious decision
describe the blinking reflex
sensory nerve in cornea is stimulated by touch
nerve impulse is sent along sensory neurone to relay neurone in CNS
impulse goes to motor neurone
motor neurones send impulse to effectors (orbicularis oculi muscles that move eyelid)
Describe the knee jerk reflex
stretch receptors in quadriceps detect stretch motion
impulse passed along sensory neurone to motor neurone in spinal cord
motor neurone carries impulse to effector muscle causing it to contract
describe process of fight or flight response
impulse from sensory neurone arrive at hypothalamus
pituitary gland releases ACTH
ACTH causes cortex of adrenal gland to release steroidal hormones
sympathetic nervous system is activated which releases adrenaline from medulla region
What are the effects of adrenaline
increased heart rate
breathing is deeper
glycogen converted to glucose (more respiration)
hairs stand on end to make animal look aggressive and bigger
How does the nervous system help to control heart rate
SAN generates electrical impulses
causes cardiac muscle to contract
rate at which SAN fires is controlled by medulla
What are chemoreceptors
chemical receptors
found in aorta, carotid artery and medulla
monitors o2 level and co2 level
What are baroreceptors
pressure receptors
found in aorta and vena cava
stimulated by high and low blood pressure
Describe structure of skeletal muscle
made up of muscle fibres
membrane is called sarcolemma
sarcolemma fold inwards to form transverse tubules(this allows impulses to spread around the membrane)
have lots of mitochondria ( which provides more ATP)
describe the structure of myofibrils
contain bundles of thick and thin filaments
made up of sarcomeres
what are the thick filament made of
myosin
what are the thin filaments made of
actin
describe the light and dark bands in myofibrils
Dark bands contain thick myosin filaments ( called A bands)
Light bands contain thin actin filaments (called I bands)
describe the structure of the sarcomere
end of sarcomere marked with Z line
middle of sarcomere is M line
Around sarcomere is H zone ( only contains myosin filaments)
describe muscle contraction in regards to filaments
Myosin and actin filaments slide over one another
this causes sarcomeres to contract
myofibrils contract
sarcomeres return to original length when relaxed
describe the structure of myosin filaments
have globular heads that are hinged( allows movement back and forth)
Each head has binding site for actin
Describe structure of actin
have binding sites of myosin heads ( called actin myosin binding sites)
What happens to muscles in resting phase
actin myosin binding site is blocked by tropomyosin( held by troponin)
myofilaments cant slide past each other
describe muscle contraction via action potential
action potential stimulates muscle cell
sarcolemma is depolarised
T-tubules are spread to sarcoplasmic reticulum
causes sarcoplasmic reticulum to release stored ca ions
ca binds to troponin
troponin changes shape
pulls out tropomyosin so that myosin can bind
How does the myosin head move
Calcium ions activate ATPase
ATPase breaks down ATP into ADP and P
this releases energy which moves the myosin head
What happens when excitation stops
Ca leaves binding sites on troponin
by active transport
ca goes to sarcoplasmic reticulum
What is a neuromuscular junction
Synapse between motor neurone and muscle cell
How do neuromuscular junctions work
ACh binds to nicotinic cholinergic receptors
neuromuscular junctions releases neurotransmitter
triggers depolarisation in muscle
muscle contracts
AChE is stored in clefts of postsynaptic membrane
What are the three types of msucle
Skeletal
Smooth muscle
Heart muscle/cardiac muscle
describe the structure and function of skeletal muscles
controlled consciously
made up of muscle fibres (have many nuclei)
some contract very quickly- used for speed and strength but you get tired quickly
some contract slowly and fatigue slowly-used for endurance and posture
describe the structure and function of smooth muscles
controlled unconsciously
found in the walls of hollow organs e.g gut and blood vessels
each muscle fibre has one nucleus
contract slowly and doesn’t fatigue
describe the structure and function of cardiac muscles
contracts on its own (myogenic)
found in the walls of the heart
branched allow nerve impulses to spread quickly through muscle
each muscle has one nucleus
contract rhythmically and doesn’t contract
