ANIMAL RESPONSES

Question 1

what does the nervous system consist of?

Answer 1

CNS- brain and spinal cord

peripheral nervous system- neurones that connect CNS to the rest of the body

Question 2

what does the peripheral nervous system consist of?

Answer 2

somatic nervous system- conscious activities

autonomic nervous system- unconscious activities

Question 3

what does the autonomic nervous system consist of?

Answer 3

sympathetic nervous system- ready for action and releases noradrenaline
parasympathetic nervous system- calms the body and releases acetylcholine

Question 4

what’s the function of the hypothalamus?

Answer 4

maintains the temperature at normal level

produces hormones which control the pituitary gland

Question 5

what is the function of the pituitary gland?

Answer 5

releases hormones and stimulates glands to release hormones

Question 6

what is the function of the medulla oblongata?

Answer 6

controls heart and breathing rate

Question 7

what is the function of the cerebellum?

Answer 7

coordination, posture and coordination of balance

Question 8

what is the function of the cerebrum?

Answer 8

vision, hearing, learning and thinking

Question 9

pathway of blinking reflex

Answer 9

sensory neurone- relay neurone-motor neurone- orbicularis oculi muscles

Question 10

pathway of knee-jerk reflex

Answer 10

stretch receptors- sensory neurone- motor neurone- effector

Question 11

pathway of sympathetic nervous system

Answer 11

nerve impulses arrive at hypothalamus which activates the hormonal and sympathetic nervous system
pituitary gland stimulated to release ACTH causing the cortex of the adrenal gland to release steroid hormones
sympathetic nervous system activated- releases adrenaline from medulla of adrenal gland

Question 12

effects of the sympathetic nervous system

Answer 12

heart rate increased
muscles around bronchioles relax- breathing= deeper
glycogenolysis
erector pili muscles contract

Question 13

control of heart rate

Answer 13

stimuli detected by pressure (baroreceptors) and chemical (chemoreceptors) receptors
electrical impulse from receptor along sensory neurone to the medulla
medulla processes information and sends impulses along motor neurones to the SAN
SAN generates electrical impulses that cause the cardiac muscle to contract

Question 14

what does the hormonal system release

Answer 14

adrenaline which binds to specific receptors in the heart
heart muscles contracts more frequently with more force
heart rate increases
more blood

Question 15

skeletal muscle

Answer 15

antagonistic pairs
striated
voluntary
contracts quickly and powerfully
fatigues quickly
cytoplasm= sarcoplasm
membrane= sarcolemma
sarcoplasmic reticulum
many mitochondria
multinucleate 
myofibril (contractile elements)

Question 16

contractile units

Answer 16

sarcomeres

Question 17

thick filament

Answer 17

myosin

Question 18

thin filament

Answer 18

actin

Question 19

cardiac muscle

Answer 19

powerful
no fatigue
myogenic
looks striped
branches- spreads impulse
intercalated discs
gap junctions- ions diffuse freely between cells

Question 20

smooth muscle

Answer 20

slow contraction
slow to tire
involuntary
less striped
2 layers- circular layer and longitudinal layer

Question 21

a band

Answer 21

thick myosin filaments with overlapping thin actin filaments

Question 22

I band

Answer 22

light band of only thin actin filaments

Question 23

Z line

Answer 23

ends of each sarcomere

Question 24

M line

Answer 24

middle of each sarcomere and middle of myosin filaments

Question 25

H zone

Answer 25

only myosin filaments

Question 26

what stays the same length when the sarcomeres contract and what gets shorter?

Answer 26

the A band

shorter: I band and H band

Question 27

myosin filaments

Answer 27

globular heads hinged so can move back and forth

myosin head has a binding site for actin and a binding site for ATP

Question 28

actin filaments

Answer 28

binding site for myosin heads called the actin-myosin binding site
tropomyosin and troponin found between actin filaments

Question 29

what is the actin-myosin binding site blocked by?

Answer 29

tropomyosin when held by troponin

Question 30

muscle contraction

Answer 30

action potential from motor neurone stimulates muscle cell and depolarises sarcolemma
depolarisation down T tubule to sarcoplasmic reticulum
releases stored calcium ions into sarcoplasm
calcium ions bind to troponin causing it to change shape
tropomyosin pulled out of actin-myosin binding site
exposes binding site so the myosin head can bind
bond formed- actin-myosin cross bridge
calcium ions activate ATPase which breaks ATP into ADP+Pi
ATP moves myosin head, pulling actin filament along
ATP breaks actin-myosin cross bridge so the myosin head detaches from actin filament
myosin head reattached to different binding site along actin filament
new actin-myosin cross bridge formed
cycle repeated as long as the calcium ions are present and bound to troponin

Question 31

when excitation stops

Answer 31

calcium ions leave their binding sites on troponin molecules and are removed by active transport back into the sarcoplasmic reticulum
troponin molecules return to original shape pulling the tropomyosin molecules with them so they block the actin-myosin binding sites
actin filaments move back into relaxed position and lengthens the sarcomere

Question 32

what provides energy for muscle contractions?

Answer 32

ATP from aerobic respiration in the oxidative phosphorylation stage
ATP from anaerobic respiration in glycolysis
CP (ATP- Creatine Phosphate) made by phosphorylating ADP

Question 33

neuromuscular junction

Answer 33

synapse between muscle cell
acetylcholine binds to nicotinic cholinergic receptors
triggers depolarisation in the post synaptic cell
muscle cell contracts if threshold reached

Question 34

acetylcholinsterase (AChE)

Answer 34

stored in clefts on postsynaptic membrane

releases to break down acetylcholine after use