Topic 6 A

Question 1

What is a tactic response?

Answer 1

Directional movement in response to a stimulus

Question 2

What is a kinetic response?

Answer 2

A non-directional (random) movement in response to a stimulus

Question 3

What do receptors do?

Answer 3

Detect stimuli

Question 4

What do effectors do?

Answer 4

Bring about a response to a stimulus

Question 5

What do sensory neurones do?

Answer 5

Transmit electrical impulses from receptor to CNS

Question 6

What do motor neurones do?

Answer 6

Transmit electrical impulses from CNS to effectors

Question 7

What do relay neurones do?

Answer 7

Transmit electrical impulses between sensory neurones and motor neurones

Question 8

What is the reflex arc?

Answer 8

Stimulus, receptors, sensory neurone, CNS (relay neurone), motor neurone, effectors response

Question 9

What is phototropism?

Answer 9

Direction of growth towards light (positive) or away from light (negative)

Question 10

What is gravitropism?

Answer 10

Growth of plant towards gravity (positive) or away from gravity (negative)

Question 11

What are auxins?

Answer 11

Growth factors produced in tips of shoots, high conc inhibit growth in roots

Question 12

What is indoleacetic acid?

Answer 12

Produced in tips of shoots and roots in flowering plants

Question 13

How does indoleacetic work in phototropism?

Answer 13

IAA conc increases on the shaded side, causing cells to elongate causing uneven growth and bend towards or away from light

Question 14

What are photoreceptors?

Answer 14

Receptors in the eye that detect light

Question 15

How do photoreceptors work?

Answer 15

Light enters eye and is absorbed by light sensitive optical pigments. Light bleaches the pigment causing a chemical change, membrane permeability for sodium ions increases. If generator potential reaches threshold it sends a nerve impulses along the bipolar neurone sending the impulse along the optic nerve to the brain

Question 16

Where are rods mainly found?

Answer 16

In the peripheral parts of the retina

Question 17

How do the rods give information?

Answer 17

In black and white

Question 18

What is the sensitivity of rods?

Answer 18

very sensitive to light many rods summated on one bipolar neurone causing weak generator potentials combine to reach a threshold and trigger and action potential

Question 19

What is the visual acuity of rods?

Answer 19

Low visual acuity many rods on one bipolar neurone, cant distinguish light from two points close together

Question 20

Where are cones mainly found?

Answer 20

In the fovea

Question 21

How to cones give information?

Answer 21

In colour (red, blue and green sensitive)

Question 22

What is the sensitivity of cones?

Answer 22

low sensitivity one cone on one bipolar neurone so more light needed to reach threshold

Question 23

What is the visual acuity of cones?

Answer 23

high visual acuity, close together one cone on one bipolar neurone, light hits two cones so two action potentials are caused hitting the brain can distinguish between two points

Question 24

What is the central nervous system made of?

Answer 24

Brain and Spinal chord

Question 25

What is the peripheral nervous system made of?

Answer 25

Neurones that connect the CNS to the rest of the body

Question 26

What are the two different systems of the peripheral nervous system?

Answer 26

Somatic and Autonomic

Question 27

What is the somatic nervous system?

Answer 27

Controls conscious activities

Question 28

What is the autonomic nervous system?

Answer 28

Controls unconscious activities

Question 29

What is the autonomic nervous system split into?

Answer 29

Parasympathetic and sympathetic

Question 30

What is the parasympathetic nervous system?

Answer 30

Calms the body down

Question 31

What is the sympathetic nervous system?

Answer 31

gets the body ready for action (fight or flight)

Question 32

What does it mean that cardiac muscle is myogenic?

Answer 32

It can contract and relax with signals from the nerves

Question 33

How is heart rate control started?

Answer 33

Starts in the sinoatrial node in the right atrium, SAN is like a pacemaker setting the rhythm of the heartbeat sending a wave of electrical activity in the atrial wall causing them to contract

Question 34

What does the band of nonconducting collagen tissue do?

Answer 34

Prevent electrical activity from being passed from the atria to the ventricle

Question 35

Where are the waves of electrical activity transferred to?

Answer 35

Atrioventricular node

Question 36

What is the atrioventricular node responsible for?

Answer 36

Passing waves of electricity to the bundle of his (slight delay so atria are emptied before ventricles contract)

Question 37

What does the bundle of his do?

Answer 37

conduct waves of electrical activity between ventricles to apex (bottom of heart)

Question 38

What does the bundle of his split into?

Answer 38

Purkyne tissue

Question 39

What does purkyne tissue do?

Answer 39

carries waves of electrical activity into muscular walls of right and left ventricles causing them to contract from the bottom up

Question 40

What controls the SAN?

Answer 40

The medulla

Question 41

What receptors detect the pressure of blood?

Answer 41

Baroreceptors in carotid and aorta

Question 42

What happens when there is high pressure in the blood?

Answer 42

Baroreceptors detect high pressure, impulse along sensory neurone to medulla, sends impulses along parasympathetic neurones. acetylcholine is secreted which binds to receptors on SAN causing heart rate to slow down and reduce blood pressure

Question 43

What happens when there is low pressure in the blood?

Answer 43

Baroreceptors detect low pressure, send impulses along sensory neurones to the medulla. Impulses along sympathetic neurones which secrete noradrenaline which bind to receptors on SAN causing heart rate to speed up increasing blood pressure

Question 44

What receptors detect the oxygen levels?

Answer 44

chemoreceptors in the aorta, carotid arteries and medulla

Question 45

What happens when there is high blood oxygen, low CO2 or high blood pH?

Answer 45

Chemoreceptors detect change, send impulses along sensory neurone to medulla, sending impulses to parasympathetic neurones, acetylcholine is secreted onto the SAN causing heart rate to decrease to return oxygen, carbon dioxide and pH levels back to normal

Question 46

What happens when there is low blood oxygen high CO2 or low blood pH?

Answer 46

Chemoreceptors detect change, send impulse along sensory neurone to medulla send impulse to sympathetic neurones, noradrenaline is secreted on SAN, heart rate increases to return oxygen, carbon dioxide and pH levels back to normal