Animal Response

Question 1

What does the human nervous system consist of?

Answer 1

Central nervous system (CNS) – the brain and the spinal cord

Peripheral nervous system (PNS) – all of the nerves in the body

Question 2

What 2 parts can the nervous system be divided into?

Answer 2

The somatic nervous system - voluntary

The autonomic nervous system - involuntary

Question 3

What are the 3 types of nerves in the somatic nervous system?

Answer 3

Sensory nerves - these consist of sensory neurones and carry impulses from sense organs to the CNS

Motor nerves - the consist of motor neurones and carry impulses from the CNS to muscles and glands

Spinal nerves - found in the spinal cord, these are mixed nerves that consist of both sensory and motor neurones

Question 4

What are the 2 parts of the autonomic nervous system?

Answer 4

The sympathetic nervous system, which controls ‘flight-or-fight’ responses

The parasympathetic nervous system, which controls the ‘rest and digest’ system

Question 5

How is the flight-or-fight response controlled by the sympathetic nervous system?

Answer 5

The sympathetic nervous system controls the release of adrenaline in the adrenal gland

It causes the heart rate to increase

increase in blood supply to muscles so they have more oxygen and glucose for respiration

It enables high-intensity activities to be an immediate response

Question 6

What are the regions in the brain?

Answer 6

Cerebrum

Hypothalamus

Pituitary gland

cerebellum

Medulla oblongata

Question 7

What are the functions of the cerebrum?

Answer 7

Controls voluntary actions
- Thought
- vision
- speech
- memory
- problem solving

Question 8

What are the functions of the cerebellum?

Answer 8

Responsible for muscle coordination and movement

Question 9

What are the functions of the Hypothalamus?

Answer 9

Control centre that monitors blood and helps maintain homeostasis

Question 10

What are the functions of the Medulla oblongata?

Answer 10

Controls involuntary actions
e.g heart rate and breathing

Question 11

What are the functions of the pituitary gland?

Answer 11

Responsible for regulating many body functions, controlling the activity of glands

Question 12

What are reflexes?

Answer 12

Rapid, unconscious actions that protect the body from harm.

They avoid the conscious part of the brain

Question 13

Explain the knee-jerk response

Answer 13

Stretch receptors in the quadriceps muscles detect that the muscle is being stretched

an electrical impulse is sent along a sensory neuron to the spinal cord

the impulses is passed on to a motor neuron which carries the impulse to the quadriceps muscle.

the muscle contracts and causes the leg to straighten

Question 14

How is the nervous system used to prepare for flight or flight?

Answer 14

Sympathetic branch of the autonomic nervous system is activated which sends signals to adrenal glands to release adrenaline

Question 15

How is the hormonal system used to prepare for flight or flight?

Answer 15

Pituitary gland releases ACTH which stimulates release of steroid hormones from adrenal cortex

Question 16

What are the effects of adrenaline on the body?

Answer 16

Stimulate breakdown of glycogen in glucose (glycogenolysis)

Directs blood flow away from digestive system towards muscles and the brain

Increases heart rate and breathing

erector pili muscles in the skin contract and hairs stand on end

Question 17

How does the cardiovascular control centre change heart rate?

Answer 17

sends impulses along the sympathetic or parasympathetic neurones which release different neurotransmitters onto the SAN

SAN modifies its firing rate to slow or speed up the heart rate

Question 18

What are the 2 types of receptors?

Answer 18

Baroreceptors (Pressure receptors) - detect changes in blood pressure and are found in the aorta and carotid artery

Chemoreceptors (Chemical receptors) - detect concentration of oxygen in the blood and pH levels and are found in the aorta and carotid artery

Question 19

How does our body respond to low blood pressure or oxygen levels?

Answer 19

the baroreceptors and chemoreceptors in the aorta and carotid artery detect that blood pressure and O2 levels are low

Impulse sent along the sensory neuron to the cardiovascular control centre

This activates the sympathetic nervous system which releases noradrenaline

Noradrenaline binds to the SAN, causing it to increase firing rate

Question 20

How does our body respond to high blood pressure or oxygen levels?

Answer 20

the baroreceptors and chemoreceptors in the aorta and carotid artery detect that blood pressure and O2 levels are high

Impulse sent along the sensory neuron to the cardiovascular control centre

This activates the parasympathetic nervous system which releases acetylcholine

Acetylecholine binds to the SAN, causing it to decrease firing rate

Question 21

What are the 3 types of muscle?

Answer 21

Skeletal muscle

cardiac muscle

smooth muscle

Question 22

Describe the structure of skeletal muscle?

Answer 22

Made of bundles of muscle fibres

Cell membrane called sarcolemma, cytoplasm called sarcoplasm

Sarcolemma folds into the sarcoplasm to fomr transverse tubules

Contain a sarcoplasmic reticulum which stores calcium ions

Multinucleated

Contain myofibrils

Question 23

What are myofibrils?

Answer 23

Long cylinders of proteins which enable the muscle fibre to contract

Made of many sarcomeres which are made of actin and myosin

Question 24

Describe the structure of a sarcomere

Answer 24

Myosin - thick filaments, dark bands

Actin - thin filament, ligh bands

I band - only actin

A band - all the myosin including the overlapped actin

Z-line - at the end of each sarcomere

M-line - the middle of the sarcomere

H-Zone - only myosin

Question 25

What happens during muscle contraction?

Answer 25

Myosin and actin filaments more closer together by sliding over one another.

Filaments stay the same size

H band shortens

I band shortens

A band stays the same (more actin)

Sarcomere shortens and they contract

Question 26

Explain the sliding filament model
(formation of actin-myosin bridge)

Answer 26

Myosin contains heads which contain binding sites for actin and ATP.

The actin-myosin binding site is blocked in resting conditions by tropomyosin and troponin

an action potential passes down the t-tubules and causes the release of Ca2+ ions from the sarcoplasmic reticulum

calcium ions bind to troponin which changes its shape and pulls the tropomyosin out of the actin-myosin binding site

myosin head can bind to actin to form a actin myosin-cross bridge

Question 27

Explain the sliding filament model
(After actin-myosin cross bridge)

Answer 27

The release of calcium ions activates ATPase which catalyses ATP to ADP + Pi

The energy produced is used by myosin heads to bend. This is known as the power stroke

Energy from ATP breaks the actin-myosin bridge and the myosin head can reattach to a binding site further along the actin filament

Question 28

What happens when the muscle is not stimulated?

Answer 28

Ca2+ ions move back into sarcoplasmic reticulum by active transport

Troponin and tropomyosin molecules return to blocking actin-myosin binding site

Sarcomere lengthens

Question 29

What are the 3 sources of ATP?

Answer 29

Aerobic respiration

Anaerobic respiration

Phosphocreatine

Question 30

How does ATP-creatine phosphate system produce ATP?

Answer 30

ADP + CP = ATP + C

Creatine phosphate is stored inside of cells and produces ATP very quickly

Anaerobic

Question 31

What happens at a neuromuscular junction?

Answer 31

Action potential arrives which stimulates the release of Ca2+

Ca2+ causes acetylcholine to fuse with presynaptic membrane and diffuse across synaptic cleft

Acetylcholine binds with the receptors on the sarcolemma which opens Na+ ion channels and Na enters the sarcolemma and the membrane depolarises