5.1.5 Plant and Animal Responses (not complete!!) Flashcards
1
Q
What is the central nervous system (CNS)?
A
- made up of the brain and the spinal cord
2
Q
What is the peripheral nervous system?
A
- made up of the neurones that connect the CNS to the rest of the body
- has two different functional systems
3
Q
What are the two different functional systems of the peripheral nervous system?
A
- somatic nervous system: controls conscious activities
- autonomic nervous system: controls unconscious activities
- this has two divisions which have opposite effects on the body
4
Q
What is the sympathetic nervous system?
A
- part of the peripheral nervous system and the autonomic nervous system
- the flight or fight system
- releases the neurotransmitter nooradrenaline
5
Q
What is the parasympathetic nervous system?
A
- rest and digest
- calms the body down
- neurones release the neurotransmitter acetylcholine
6
Q
What does the hypothalamus found and what does it control?
A
- found just above the pituitary gland
- maintains body temperature
- hypothalamus produces hormones and controls the pituitary gland
7
Q
Where is the pituitary gland and what does it do?
A
- found beneath hypothalamus
- controlled by the hypothalamus
- releases hormones and stimulates other glands e.g. adrenal glands to release their hormones
8
Q
Where is the medulla oblongata and what is its function?
A
- at the base of the brain, top of the spinal cord
- automatically controls breathing rate and heart rate
9
Q
Where is the cerebellum and what does it control?
A
- underneath the cerebrum, at the back
- has a folded cortex
- controls muscle coordination, posture and coordination of balance
10
Q
Where is the cerebrum and what does it control?
A
- largest part of the brain
- divided into the two cerebral hemispheres
- has a thin outer layer called cerebral cortex, which is highly folded
- involved in vision, hearing, thinking, learning
11
Q
Describe the blinking reflex
A
- sensory nerve endings in the cornea are stimulated by touch
- a nerve impulse is sent along the sensory neurone to a relay neurone in the CNS
- impulse is then passed from the relay neurone to motor neurones
- motor neurones send impulses to the effectors, the orbicularis oculi muscles that move your eyelids
- these muscles contract causing your eyelids to close quickly and prevent your eye from being damaged
12
Q
Describe the knee jerk reflex
A
- stretch receptors in the quadriceps muscle detect that the muscle is being stretched
- a nerve impulse is passed along a sensory neurone, which communicates directly with a motor neurone in the spinal cord
- no relay neurone involved
- motor neurone carries the nerve impulse to the effector (quadriceps muscle), causing it to contract so the lower leg moves forward quickly
13
Q
Describe what happens during fight or flight response?
A
- nerve impulses from sensory neurones arrive at the hypothalamus, activating both the hormonal system and the sympathetic nervous system
- the pituitary gland is stimulated to release the hormone ACTH
- this causes the cortex of the adrenal gland to release steroidal hormones
- the sympathetic nervous system is activated, triggering the release of adrenaline from the medulla region of the adrenal gland which then has these effects: (see other flashcard)
14
Q
What effects do adrenaline and sympathetic nervous system have during fight or flight response?
A
- heart rate is increased, so blood is pumped around faster in the body
- muscles around the bronchioles relax, so breathing is deeper
- glycogen is converted to glucose, so more glucose is available for muscles to respire
- muscles in the arterioles supplying the skin and gut constrict and muscles in the arterioles supplying the heart, lungs and skeletal muscles dilate, so blood is diverted from the skin in the gut to the heart, lungs, and skeletal muscles
- erector pili muscles in the skin contract, making hairs stand on end so the animal looks bigger
15
Q
How do the nervous and hormonal systems control heart rate?
A
Nervous system:
- the sinoatrial node (SAN) generated electrical impulses that cause the cardiac muscles to contract
- the rate at which the SAN fires are unconsciously controlled by a part of the brain called the medulla
- animals need to alter their heart rate to respond to internal stimuli
- stimuli are detected by pressure receptors and chemical receptors:
- baroreceptors in the aorta and vena cava are stimulated by high and low pressure
- chemoreceptors in the aorta, the carotid artery and in the medulla monitor the oxygen level in the blood and also CO2 and pH
- electrical impulses from receptors are sent to the medulla along sensory neurones
- the medulla process information and sends impulses to the SAN along motor neurones (look at the table)
Hormonal:
- helps to control heart rate by releasing adrenaline
- adrenaline bonds to specific receptors in the heart
- this causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and heart pumps more blood
16
Q
What is important about the circulatory system?
A
17
Q
How can heart action be modified to adapt to the needs of tissues?
A
24
Q
What kind of sensory input to the cardiovascular centre changes heart rate
A
- stretch receptors in the muscles detect movement of the limbs
- sends impulses too cardiovascular centre informing that extra oxygen is needed
- increase in heart rate
- more see pic
25
Q
What is used to artificially control heart rate?
A
28
Q
Describe the structure involuntary (smooth muscle) and where it is found
A
- consists of individual cells
- they are tapered at both ends
- at rest each cell is about 500µm long and 5µm wide
- each cell contains a nucleus and bundles of actin and myosin
30
Q
Describe the structure and location of cardiac muscle
A
31
Q
Describe the contraction of cardiac muscle
A
32
Q
What does cardiac muscle look like?
A
33
Q
Describe the structure of voluntary (skeletal or striated) muscle
A
- the muscles are arranged in pairs called antagonistic pairs
- muscle cells form fibres of about 100µm in diameter
- each fibre is multinucleate and surrounded by a membrane called the sarcolemma
- muscle cell cytoplasm is known as sarcoplasm
- it is specialised to contain many mitochondria and an extensive sarcoplasmic reticulum
- contents of fibres are arranged into a number of myofibrils, which are contractile elements
- these myofibrils are divided into a chain of subunits called sarcomeres
- sarcomeres contain the protein filaments actin and myosin
- actin and myosin are arranged into a banded pattern,
- dark bands are A bands and lighter are I bands
34
Q
What muscle is this?
A
- voluntary muscle
36
Q
How is muscle contraction stimulated?
A
- action potentials arriving at the end of the axon open calcium ion channels in the membrane
- calcium ions flood into the end of the axon
- vesicles of acetylcholine move towards and fuse with the end membrane
- acetylcholine molecules diffuse across the fap and fuse with receptors in the sarcolemma
- this opens sodium ion channels, which allow sodium ions to enter the muscle fibre, causing depolarization of the sarcolemma
- a wave of depolarization spreads along the sarcolemma and down transverse tubules into the muscle fibre
