Coordination and Response - Bio

Please provide the context and the sentence fragment for me to assist you with the Define nerve impulse an electrical signal that passes along nerve cells called neurones in one

direction

What is the central nervous sytem made up of? Brain and spinal cord

What is the peripheral nervous system made up

of?

Cranial and spinal nerves

It connects the central nervous system to the body

What are cranial nerves? Connect the brain with all other organs in head, thorax, abdomen

What are spinal nerves? Connect the brain with the arms, thorax, abdomen and legs

What is the human nervous system made up of? central nervous system (brain and spinal cord) and peripheral nervous system

What is nerve made up of? Lots of neurones / nerve cells

Define voluntary action Reactions that we choose to make (involve the brain) e.g. catching a ball

Define involuntary action A automatic response that does not involve a decision/thought

Define reflex action Automatically and rapidly intergrating and coordinating stimuli with the

responses of effectors (msucles and glands)

Compare and contrast voluntary and involuntary

actions

Draw a sensory neuron

Draw a relay neuron

Draw a motor neuron

Describe how a structure of a neurone is related to

its function [3]

Long = transmit impulse over long distances

Mitochondria to release energy for transmission impulse

Vesicles release neurotransmiters

Receptors on post-synaptic neurone and vesicles on pres-synpatic neurone

causes the impulse to flow in one direction

Describe the process of a voluntary action Seven Rainy Summers Can Make Everyone Remember:

Stimulus, receptor, sensory neuron, central nervous system, motor neuron,

effector, response

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A person kicks a football. Describe the voluntary

response

The stimulus is the ball coming towards the person.

The receptors in the eyes detect the stimulus.

A nervous impulse travels down a sensory neuron

When the impulse arrives at a synapse (gap between neurones), the vesicles

in the pre-synaptic neuron release a neurotransmitted that diffuses across the

synapse, and reaches the post-synaptic neuron and binds with receptor

molecules.

The nervous impulse reaches the brain and spinal cord (central nervous

system), which coordinates the response

The nervous impulse then travels down a motor neuron, to the effector, the

muscles in the leg.

The reponse is the person kicks a football

Describe the process of an involuntary action Seven Rainy Summers Can Make Everyone Remember: Stimulus, receptor,

sensory neuron, RELAY NEURON, motor neuron, effector, response

Suggest why reflexes occur in people who are

unconscious [1]

Involuntary

Receptors still function

A person touches a hot object. Describe the reflex

reponse

The stimulus is the hot object touching the skin.

The receptors in the skin detect the stimulus.

A nervous impulse travels down a sensory neuron

When the impulse arrives at a synapse (gap between neurones), the vesicles

in the pre-synaptic neuron release a neurotransmitted that diffuses across the

synapse, and reaches the post-synaptic neuron and binds with receptor

molecules.

The nervous impulse travels down a relay neuron (in the spinal cord, by-

passing the brain)

The nervous impulse then travels down a motor neuron, to the effector, the

muscles in arm.

The reponse is the hand moves away from the hot object

Suggest the advantages of having refleces. You

may refer to an example to illustrate your answer.

[3]

Rapid response can protect us from danger

An example is automatically moving our hand away when close to a hot

object

What is the coordinator of a voluntary action? The brain (i.e. it coordinates the response!)

What is the role of human nervous syste,? coordinated and regulate body functions

What is a stimulus? A change in the environment

Define synapse Junction between two neurones. Ensures the impulse travel in one direction

only

What are receptors? Cells that detect a stimulus

Where in the body are receptors? skin, ears, eyes, tongue, nose

What are effectors? Muscles or glands that carry out the response to the stimulus

Why are neurones surrounded by myelin? It is a layer rich in fat, that provides insulation, and therefore the impulses can

travel very quickly

Draw and label a synapse

Describe what happens at the synapse When the impulse arrives at a synapse (gap between neurones), the vesicles

in the pre-synaptic neuron release a neurotransmitter that diffuses across

the synapse, reaches the post-synaptic neuron and binds with receptor

molecules. The nervous impulse then continues down the neuron.

How can drugs affect synapses? Influencing the release of neurotransmitters or interacting with the receptors

on the post-synaptic membrane

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What affect do excitatory drugs have on synapses? stimlate the release of neurotransmitters, increasing activity

Name an example of an excitatory drug amphetamines - increase brain activity / alertness

What affect do inhibitory drugs have on synapses? reduce the effect of neurotransmitters / block the receptors that

neurotransmitters bind it

Name an example of an inhibitory drug heroin, beta-blockers. Reduce the feeling of pain

Define sense organs group of receptor cells responding to specific stimuli (light, sound, touch,

temperature, chemical)

Draw and label the human eye

What is the function of the cornea? refracts light

What is the function of the iris? controls how much light enters pupil

What is the function of the lens? focuses light onto retina

What is the function of the retina? contains light receptors (cones and rods), some sensitive to light of different

colours

What is the function of the optic nerve? carries impulses to the brain

Describe the pupil reflex in bright light To make the pupil diameter smaller the radial muscles relax and the circular

muscles contract (Remember- muscles get short and fat when they are

contracting)

Describe the pupil reflex in dim light To make the pupil diameter larger the radial muscles contract and the circular

muscles relax (Remember- muscles get short and fat when they are

contracting)

Explain why the change in pupil size as the light is

switched on is necessary [2]

So less light enters the eye to protect the retina/rods/cones

What type of response is a pupil reflex? Involuntary response

Why are the radial and circular muscles of the eye

antagonistic pairs?

work together in pairs - when one contracts, the other relaxes

What is accomodation? The way the lens changes shape to focus at objects near and far away from

the eye

How is light refracted so that it focuses on the

retina?

Light is refracted by the corena and aqueous humour. The lens then focuses

the light further.

Explain how light is focused to be able to see a

distant object

The ciliary muscle relaxes (hole gets wider)

The suspensory ligaments get tighter

The lens gets flatter/elliptical (thin) shape

Light is refracted less to focus on the retina

Explain how light is focused to be able to see a

close object

The ciliary muscle contracts (hole gets smaller)

The suspensory ligaments get slacker

The lens gets rounder/spherical (fatter)

Light is refracted more to focus on the retina

What is the function of rods? Detect light of low intensity and convert the light to electrical impulses. Rods

provide night vision and give black and white vision. They are sensitive in

dim light

What is the function of cones? Sensitive to high light intensity, three different kinds of cones absorbing light

of different colours for colour vision Each cone is connected to its own

neuron to the brain so gives a very detailed image

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Outline how humans are able to see in colour [3] Cones detect light of three different wavelengths and converts light into

electrical impulses which is carried along the optic nerve to the brain where it

interprets the impulse in terms of colours.

Does the fovea contain rods or cones? Lots of cones - most sensitive part of the retina

Describe the distribution of rods and cones on the

retina

No rods and cones on fovea (centre of retina). Many rods, few cones on the

rest of the retina

Define a hormone a chemical substance, produced by a gland and carried by the blood, which

alters the activity of one or more specific target organs

What hormones does the adrenal gland secrete? adrenaline - allows 'flight or fight response' by increasing heart rate,

breathing rate, widening pupils

What hormone does the pancrease secrete? And

what is the function? insulin/glucagon - controls blood sugar levels

What hormone do the testes secrete? And what is

the function?

testosterone - stimulates the secondary male features and body hair

What hormone do the ovaries secrete? oestrogen

Describe the effects of adrenaline Increases heart rate - more oxygen to muscle cells, more respiration, faster

contraction to run away

Increases breathing rate - more oxygen uptake and carbon dioxide excreted

Widens pupils

Increases blood glucose concentration

Fight or flight response

Describe situations when adrenaline would be

released from the gland into the blood [3]

During a fight or flight response

When in dangerous situations

Display aggression

Describe the effects of testosterone Increase muscle mass, increase body hair, controls growth and development

Describe the effects of oestrogen Growth of breasts, more body hair, menstrural cycle, controls growth and

development

Compare and contrast the nervous and endocrine

system

Define homeostasis The maintenance of a constant internal environment. The control of internal

conditions within set limits

Define negative feedback

A regulatory mechanism that returns a condition to its optimum e.g. body

temperature to 37C

Give examples of of constant internal conditions in

the human body

Blood sugar (glucose) concentration. Water, carbon dioxide, oxygen

concentration of the blood. pH of the blood. Body temperature

Name 2 hormones that control blood sugar levels insulin and glucagon

What is glycogen? A complex carbohydrate / polysaccharide made up of many glucose

molecules. Stored in the liver and muscle cells

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Describe the response of the human body when

blood glucose level decreases

Increase in blood glucose concentration is detected by the pancreas. The

pancreas secretes GLUCAGON which travels in the bloodstream to the liver.

The liver breaks down glycogen into glucose using enzymes in liver cells,

which diffuses into the bloodstream, increasing blood glucose levels. This is

an example of homeostasis/negative feedback.

Suggest why blood sugar levels may decrease Long time since last meal / been asleep / after prolonged exercise

Describe the response of the human body when

blood glucose level increases

Increase in blood glucose concentration is detected by the pancreas. The

pancreas secretes INSULIN which travels in the bloodstream to the liver. The

liver absorbs more glucose from the bloodstream and stores it as glycogen

(this also occurs in the muscles) using enzymes in liver cells, decreasing blood

glucose levels. This is an example of homeostasis/negative feedback.

Suggest why blood sugar levels may increase Recently eaten a meal

Describe how negative feedback ensures blood

glucose concentration is controlled

The pancreas makes insulin to stimulate the liver to absorb glucose,

decreasing blood glucose concentration, or makes glucagon to stimulate the

liver to break down glycogen into glucose, increasing blood glucose

concentration

Name the largest organ in the body The skin

List 3 functions of the skin Protects the body from damage, stops pathogens from entering, prevents too

much water loss, derects changes in temperature, detects pressure (touch)

and pain, loses heat by conduction, convection, radiation and evaporation

Identify on a diagram: hairs, hair erector muscles,

sweat glands, receptors, sensory neurones, blood

vessels and fatty tissue

List the responses that occur in the human body if

body temperature increases

Sweating may occur (and a smaller volume of urine is produced). Evaporation

of sweat causes cooling of the body. Arterioles (blood vessels supplying the

skin capillaries) dilate, more heat is lost by radiation from the surface of the

skin, hair erector muscles relax (causing hairs to stay flat on the skins surface)

Behavioural responses (taking off outer layers of clothing)

Describe what happens when body temperature

increases

The thermoregulatory centre in the brain detects changes in blood

temperature, causing sweating to occur, as evaporation of sweat cools the

body. Arterioles dilate (vasodilation) supplying more blood to the surface of

the skin, and more heat loss by radiation.

List the responses that occur in the human body if

body temperature decreases

Arterioles (blood vessels supplying the skin capillaries) constrict, so less heat

is lost by radiation from the surface of the skin. Sweating does not occur.

Muscles contract causing shivering requires aerobic respiration, which

releases heat energy. Hair erector muscles contract, causing hairs to stand up

trapping a layer of insulating air. Behavioural responses (putting on more

clothes)

Describe what happens when body temperature

decreases

The thermoregulatory centre in the brain detects changes in blood

temperature, causing shivering to occur; the contraction of muscles requires

aerobic respiration which releases heat energy. Hair erector muscles also

contract causing hairs to stand on end trapping a layer of insulating air.

Arterioles constrict (vasocontriction) supplying less blood to the surface of the

skin, and less heat loss by radiation.

Describe how the hair, receptors, sweat glands,

and fat help to maintain a constant body

temperature [4]

The hair contracts and stands up when too cold and as air is a good insulator,

it will prevent heat loss

The temperature receptor detects the change in temp and sends an impulse

to the CNS

The sweat gland produces sweat, which evaporates to cool down the body

The fat acts as an insulator.

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Explain how negative feedback is involved in the

control of body temperature [3]

The change in temperature is detected and the body carries out a corrective

action to keep the temperature at the norm.

Explain the importance of regulating body

temperatures in humans [4]

Prevent enzymes from denaturing

Optimum temperature for enzymes

Maintain constant rate of reaction

Prevent heat stroke/chills

Explain how vasodilation and vasoconstriction are

involved in maintaining body temperature

When body temperature decreases, arterioles (blood vessels supplying the

skin capillaries) contrict (vasocontriction) supplying less blood to the surface

of the skin, and less heat loss by radiation.

When body temperature decreases, arterioles dilate (vasodilation) supplying

more blood to the surface of the skin, and more heat loss by radiation.

What causes type 1 diabetes? Occurs when the body cannot produce insulin

What are the symptoms of type 1 diabetes? Feeling thirsty

Tired/fatigue

Weight loss

Glucose present in urine

Vomitting

What are the treatment for type 1 diabetes? Injecting insulin

Regular glucose tests

Controlled diet - avoid sugary foods

Define gravitropism a response in which parts of a plant grow towards or away from gravity

Define photostropism a response in which parts of a plant grow towards or away from the direction

from which light is coming

Define positive phototopism a response in which parts of a plant grow towards the direction from which

light is coming e.g. shoots!

Define negative gravitropism a response in which parts of a plant grow away from gravity e.g. the shoots!

Describe how shoots bend towards the light Auxin is made in the tip of the shoot. There is an unequal distribution of

auxin. Auxin accumulates on the shaded side of the shoot. Auxin causes cell

elongration, so the shoot bends towards the light

Describe how roots bend towards gravity There is an unequal distribution of auxin. Auxin accumulates on the LOWER

side of the root. Auxin inhibits cell elongration, so the root bends downwards

towards gravity

What is the difference between the effect of auxin

on shoots and roots?

In shoots, auxin STIMULATES cell elongation. In roots, auxin INHIBITS (I.e.

stops) cell elongation

What is a function of synthetic auxin? Weedkillers - absorbed by broad leaved weeds = increases growth rate, the

plant cannot photosynthesise/produce enough glucose fast enough for the

rapid growth rate, so the plant dies

Draw a diagram of a plant shoot and root and the

distribution of auxin in response to gravity

Explain why it is important for their early growth

that the roots and shoots of the seedlings respond

to gravitropism [2]

So the roots grow downwards to absorb more water and the shoots grow

upwards so that the leaves can absorb more sunlight for photosynthesis

Suggest how weedkillers spread throughout the

plant [2]

Weedkillers spread by diffusion and are absorbed where it enters the phloem

and are translocated.