2.5 Response and Regulation

Question 1

What is the main purposes of the nervous system?

Answer 1

• Detect changes in environment
• Control the actions of the body
• To coordinate responses by linking different actions in a specific way, and making decisions whether any action is needed (and what action it should be)

Question 2

What are the two nervous systems?

Answer 2

CNS- Central Nervous System

PNS- Peripheral Nervous System

Question 3

What is the CNS and it’s purpose?

Answer 3

The Central Nervous System consists of the brain and the spinal cord.
Its purpose is to coordinate a response by determining whether to respond and what action to take.

Question 4

What is the process of the reflex arc?

Answer 4

PNS

1) Stimulus (e.g. a pin)
2) Receptor (A sensory neuron that responds to the stimulus
2. 5) The impulse is past through the sensory neuron, up the dorsal root and into the spinal cord.

CNS- processes, sends sensations to brain

3) The impulse moves across the gap in the spinal cord (called the synapse) through the relay neuron.
3. 5) The relay neuron sends another impulse to the motor neuron which passes out through the ventral root to the effector

PNS
4) The effector (either a muscle or gland) is then activated and carries out a response (e.g. moves hand away from pin).

Question 5

What is the purpose of the PNS?

Answer 5

To send signals to and from the CNS by controlling the sensory and motor neurons.

Question 6

What is a sensory neutron?

Answer 6

A neutron that detects a stimulus (internally or externally) and sends an impulse to the CNS (in the spine)

Question 7

What is a motor neuron?

Answer 7

A neutron that sends an impulse from the CNS to an effector (muscle or gland)

Question 8

What is a relay neutron?

Answer 8

A neutron that sends an impulse from the sensory neutron to the motor neutron in the synapse (area of spine)

Question 9

What in the name of the information a neuron sends?

Answer 9

An impulse.

NOT a single (too vague).

Question 10

What is phototropism?

Answer 10

The plants growth in response to light.
Positive phototropism- when plant grows towards light
Negative phototropism- when a plants grows away from light.

Question 11

What is Gravitropism?

Answer 11

A plants tendency to grow away or towards the pull of gravity.
Root have a positive gravitropism (they grow with gravity)
Stems have a negative gravitropism (they grow against gravity).

Question 12

How do plants send impulses that control itself?

Answer 12

They are controlled by a hormones called auxin.

Question 13

What are the parts of an eye?

Answer 13

Cornea- outer layer of eye that lets light in (Transparent)

Iris- Coloured part of eye that controls the dilatation of the pupil

Lens- Focuses light onto the retina

Pupil- A gap in the iris that light passes through

Sclera- Outer white part of the eye that acts as a protective layer

Choroid- Black inner layer that reduces internal reflections

Retina- Light sensitive part of the eye

Blind spot- A gap in the retina where the optic nerve is attracted to the eye

Optic nerve- sends information from the retina and sends it to the brain.

Question 14

What is the purpose of homeostasis?

Answer 14

To sustain a constant internal environment inside the body.

Question 15

What is the process when blood glucose levels are too high?

Answer 15

• (Stimulus) High glucose concentrations in blood
• Pancreas detects this stimulus (Receptor)
• The pancreas then releases the hormone insulin into the blood.
• The insulin stimulates cells in the liver to turn glucose into glycogen
• Normal blood glucose levels are restored

Question 16

What is the process when blood glucose levels are too low?

Answer 16

• (Stimulus) Blood glucose levels drop
• Pancreas detects this stimulus (Receptor)
• The Pancreas then releases the hormone glucagon
• The glucagon stimulates cells in the liver to convert the glycogen back into glucose
• Glucose goes into the blood and normal levels are restored.

Question 17

What are the hormones and substances in the homeostasis of glucose levels?

Answer 17

Substances

• Glucose
• Glycogen

Hormones

• Insulin- Tells cells in the liver to convert glucose into glycogen where it is stored
• Glucagon- Tells cells in liver to convert glycogen back into glucose.

Question 18

What is vasoconstriction?

Answer 18

This is where blood vessels near the surface constricted when it’s cold so less blood flows through them and less heat is lost to the air.

Question 19

What is vasodilation?

Answer 19

When blood vessels near the surface dilate when it’s hot to let more blood flow through them so more heat is lost to the air.

Question 20

What is our bodies response to coldness? (4)

Answer 20

• Hairs erect (Hair erector muscles)
• No sweat is produced
• Vasoconstriction
• You shiver

Question 21

What is our bodies response to heat?

Answer 21

• Sweating
• Increased breathing rate
• Muscles relax (no shivering)
• Vasodilation

Question 22

What is the makeup of the skin?

Answer 22

• Hair erector muscle (lifts up hairs when cold)
• Sensory nerve endings (Detects stimuluses)
• Sweat glands (produces sweat)
• Sweat duct (Passes sweat to the surface)
• Blood capillaries (for vasoconstriction/dilation)
• Fatty tissue at the bottom (Acts as insulation and energy store).

Question 23

What is a negative feedback (loop)?

Answer 23

A mechanism in organisms that keeps a particular internal factor within a range (e.g. the blood glucose levels).

Question 24

What glands produce hormones?

Answer 24

Endocrine glands