5.5 Animal Responses Flashcards
1
Q
Define autonomic nervous system
A
part of the nervous system responsible for controlling the involuntary motor activities of the body
2
Q
Define central nervous system
A
the central part of the nervous system composed of the brain and the spinal cord
3
Q
Define peripheral nervous system
A
the sensory and motor nerves connecting the sensory receptors and effectors to the CNS
4
Q
Define somatic nervous system
A
the motor neurones under conscious control
5
Q
What is the nervous system divided into?
A
CNS and PNS
6
Q
What is the CNS divided into?
A
brain and spinal cord
7
Q
What is the PNS divided into?
A
sensory system and motor system
8
Q
What is the motor system divided into?
A
somatic nervous system and autonomic nervous system
9
Q
What type of neurones are in the brain?
A
mostly relay
mostly non-myelinated (grey matter)
10
Q
What type of neurones are in the spinal cord?
A
mostly relay
mostly grey, some white matter
11
Q
What does the peripheral nervous system do?
A
ensures rapid communication between the sensory receptors, the CNS and the effectors
12
Q
What does the somatic nervous system control?
A
mostly skeletal muscle
mostly myelinated
1 neurone
voluntary
13
Q
What does the autonomic nervous system control?
A
not voluntary control (eg glands, cardiac muscle, sooth muscle)
mostly non-myelinated
usually at least 2 neurones
14
Q
What can the autonomic nervous system be divided into?
A
Sympathetic and parasympathetic nervous sytems
15
Q
What does the sympathetic nervous system do?
A
Prepares the body for activity
16
Q
What does the parasympathetic nervous system do?
A
Conserves energy
17
Q
Differences in the organisation of sympathetic and parasympathetic nervous systems?
A
- Sympathetic has many different nerves to many different effectors/ parasympathetic has a few nerves to a lot of effectors
- in S, the ganglia lie just outside CNS, in P ganglia are in effector tissue
- in S there are short pre-ganglionic neurones, in P they are long
- in S there are long post-ganglionic neurones, in P they are short
18
Q
What is a ganglion?
A
Structure that contains many nerve cell bodies
19
Q
What is the neurotransmitter of the sympathetic nervous system?
A
noradrenaline
20
Q
What is the neurotransmitter of the parasympathetic nervous system?
A
Acetylcholine
21
Q
Effects of sympathetic system
A
- increased heart rate
- dilated pupils
- increased rate of ventilation
- reducing digestive activity
- orgasm
22
Q
Effects of parasympathetic system
A
- decreased heart rate
- constricted pupils
- reduced ventilation rate
- increased digestive activity
- sexual arousal
23
Q
What does the cerebrum do?
A
- conscious thought
- conscious actions
- emotion
- reasoning
- memory
24
Q
What does the cerebellum do?
A
coordinates muscles, balance and posture
25
What does the medulla oblongata do?
controls breathing rate and heart rate
26
What does the pituitary gland do?
controls hormone release by body glands
27
What does the hypothalamus do?
Homeostatic control
28
Where is the visual area of the brain and what is it called?
Occipital lobe, back of the brain
29
Define knee jerk reflex
a reflex action that straightens the leg when the tendon below the knee cap is tapped
30
Define reflex action
a response that does not involve any processing by the brain
31
What controls movement apart from the cerebellum?
The motor cortex on the top of the brain
32
Describe the blinking reflex
- sensory nerve endings in cornea stimulated by touch
- impulse goes along sensory neurone to relay neurone in CNS
- relay to motor neurones
- effectors = orbicularis oculi muscles that move your eyelids
- muscles contract and eyelids close
33
Describe the knee jerk reflex
- stretch receptors in the quadriceps muscle detected the muscle is stretched
- sensory neurone communicates directly with a motor neurone in the spinal cord
- motor neurone to effector (quad) and it contracts
34
What is the knee jerk reflex used for?
To maintain posture and balance
35
Why do we have reflexes?
Survival value
36
What type of reflex is the blinking reflex?
Cranial reflex (passes through brain but no processing)
37
Briefly describe the optical reflex
Stimulus detected by retina
Travels to optical centre in cerebral cortex
Slower than corneal reflex
38
What type of reflex is the knee jerk reflex?
Spinal reflex
39
What do you tap in the knee jerk reflex?
Patellar tendon
40
What is involved in the fight or flight response?
- heart rate increased
- muscles around bronchioles relax for deeper breathing
- glycogen to glucose
- arterioles supplying skin and gut constrict
- arterioles supplying the heart, lungs and skeletal muscles dilate
- erector pili muscles in the skin contract
- pupils dilate
- endorphins released by the brain
41
What does the hypothalamus do in response to a threat?
Releases CRH and TRH which stimulate the pituitary gland
| Activates sympathetic nervous system
42
What hormones does the pituitary gland release?
ATCH (adrenal cortex: corticoid hormones) and TSH (thyroid gland: thyroxine)
43
What does the sympathetic nervous system do in response to threat?
Activates adrenal medulla - secretion of adrenaline into bloodstream
44
What does thyroxine do?
- acts on every cell in the body
| - increases metabolic rate
45
How can the heart accommodate changing demands of tissues?
- change heart rate
- change force of contractions of the heart
- change stroke volume
46
Names of two nerves that got from the medulla oblongata to the SAN
Accelerans nerve and the vagus nerve
47
Describe the accelerans nerve
sympathetic
releases noradrenaline
increases heart rate
48
Describe the vagus nerve
parasympathetic
releases acetylcholine
decreases heart rate
49
How does the cardiovascular centre in the medulla oblongata control whether to send more signals down the vagus nerve or the accelerans nerve?
- muscle stretch receptors
- chemoreceptors in carotid arteries, aorta and brain (monitor pH)
- stretch receptors in the walls of the carotid sinus (monitor blood pressure)
50
Where are artificial pacemakers connected?
either directly to the SAN or to the ventricle muscle
51
What are the three types of muscle?
skeletal (voluntary/striated)
cardiac
smooth (involuntary)
52
How would the medulla oblongata affect heart rate in response to an increase in the concentration of carbon dioxide in the blood?
- CO2 forms HCO3- and H+
- changes in pH detected by receptors in carotid arteries
- send impulses to medulla oblongata
- increases impulses along accelerans nerve to SAN
- heart beats faster
53
What is the membrane of muscle fibre cells called?
sarcolemma
54
Whats a muscle cells cytoplasm called?
sarcoplasm
55
What are T tubules?
transverse tubules
folds of the sarcolemma into the sarcoplasm
help spread electrical signals throughout sarcoplasm so they can reach all part s of the muscle fibre
56
What are thin filaments made of?
Actin
57
What are thick filaments made from?
Myosin
58
Features of cardiac muscle
- myogenic
- made of muscle fibres connected by INTERCALATED DISCS
- branches so nerve impulses can spread quickly
- each fibre has one nucleus
- each fibre is about 0.1mm long
- dont fatigue
- looks striped
59
What are intercalated discs for?
low electrical resistance so nerve impulses can pass easily between cells
60
Features of smooth muscle
- not striped
- walls of hollow internal organs
- each fibre has one nucleus
- each fibres is about 0.2mm long
- contract slowly
- dont fatigue
61
Features of skeletal muscle
- voluntary
- many nuclei
- fibres can be many cm long
- has cross-striations
62
How does adrenaline act on cells?
```
its is a first messenger
binds to receptor
G protein activated
stimulates activity of adenyl cyclase
ATP to cAMP which is a second messenger and acts on various enzymes
```
63
What is a motor unit?
All of the muscles supplied by one motor neurone
64
Why does excitation between cardiac muscle cells travel faster than it does between connected neurones?
Excitation in cardiac cells travels through gap junctions instead of through synapses. This is quicker as non need to wait for fusion of vesicles or diffusion across synapse
65
What is the neurotransmitter and receptor called at neuromuscular junctions?
aceytlcholine and nicotinic cholinergic receptors
66
What breaks down acetylcholine after it has been used in the neuromuscular junction?
Acetylcholinesterase stored in clefts on the postsynaptic membrane
67
What is I-band?
Light band
| Thin actin filaments only
68
What is A-band?
Dark band
| thick myosin filaments and some overlapping thin actin filaments
69
What is the H-zone?
Only myosin filaments
70
What happens to the I-band and the H-zone when the muscle contracts?
They get shorter
71
What stays the same length when muscle contracts?
A-bands
72
Which filaments have globular heads and binding sites?
Myosin filaments
73
What are the binding sites on myosin filaments?
for actin
for ATP
for tropomyosin
Ca2+?
74
What are the binding sites on actin filaments for?
myosin heads
| actin-myosin binding sites
75
What are the proteins that are found between actin filaments called?
tropomyosin and troponin
76
What does troponin do?
keeps tropomyosin and actin tethered
77
What does tropomyosin do?
winds around actin
| blocks myosin binding sites on actin
78
When a muscle is resting what is happening?
the actin-myosin binding site is blocked by tropomyosin which is held in place by troponin
myofilaments cant slide past each other
79
How is muscle contraction triggered?
The action potential depolarises the sarcolemma
Depolarisation spreads down t - tubules to the sarcoplasmic reticulum
The sarcoplasmic reticulum releases stored Ca2+ ions into the sarcoplasm
These bind to troponin and it changes shape
The tropomysoin gets pulled out of the actin-myosin binding site on the actin filamet
This exposes the binding site and the myosin head can bind
80
What is the bond called between a myosin head and an actin filament?
Actin-myosin cross bridge
81
How do we get energy needed to move the myosin head?
calcium ions also activate the enzyme ATPase which breaks down ATP
This energy is used to move the myosin head a pull the actin filament
82
How does the actin-myosin cross bridge break?
ATP provides energy when it detaches
83
What happens when muscle contraction has finished?
Ca2+ ions are pumped quickly back into the sarcoplasmic reticulum
84
What are the three main ways of generating ATP?
1) Aerobic respiration
2) Anaerobic respiration
3) Creatine phosphate
85
How does aerobic respiration generate energy?
Mostly via oxidative phosphorylation
86
How does the ATP-creatine phosphate system generate energy?
```
ATP made by adding a phosphate group taken from creatine phosphate (CP) to ADP
very quick
short bursts of vigorous exercise
anaerobic and alactic
in sarcoplasm
```
87
What does an actin filament consist of?
two chains of actin subunits twisted around each other
88
What is wound around actin filaments?
tropomyosin
89
What does troponin consist of?
3 polypeptides
- 1 binds to actin
- 1 binds to tropomyosin
- 1 binds to calcium when it is available
90
What happens during the power stroke?
ADP + Pi are released from the myosin head
