Unit 5: Homeostasis

Question 1

Negative Feedback System

Answer 1

A response that involves the body stopping small changes from getting to large

(Thermostat)

Question 2

Positive Feedback System

Answer 2

This response makes small changes larger to pull the body out of homeostasis.

(Childbirth)

Question 3

What are the 3 stages of Urine formation?

Answer 3

1. Filtration
2. Reabsorption
3. Secretion

Question 4

Filtration

Answer 4

Water is filtered out and solutes dissolved when blood is forced through the GLOMERULUS and into BOWMANS CAPSULE

Question 5

Filtration (Substances Transported)

Answer 5

Sodium & Chloride (active transport)

Water (passive transport)

Question 6

Reabsorption:

Answer 6

When nutrients are reabsorbed from the filtrate back into blood via active AND passive transport.

Question 7

Reabsorption (Substances Transported)

Answer 7

Bicarbonate, salt, water, potassium, hydrogen and ammonia.

Question 8

Secretion:

Answer 8

Reabsorption of nutrients from the blood into the nephron transport. Distal tube regulates potassium and salt concentration.

Question 9

Secretion (Substances transported)

Answer 9

Salt, Potassium, hydrogen, bicarbonate and ammonia.

Question 10

Estrogen

Answer 10

Stimulates thickening of the endometrium

Question 11

Growth Hormone

Answer 11

Regulates the growth of long bones

Question 12

Epinephrine

Answer 12

Produced by stress

Question 13

Insulin

Answer 13

Increase the bodies absorption of glucose

Question 14

Thyroxine

Answer 14

Regulates cell metabolism

Question 15

Testosterone

Answer 15

Stimulates the development of sperm

Question 16

Explain a feedback loop that regulates blood sugar

Answer 16

1. High blood sugar
2. Insulin released from beta-cells of the pancreas
3. Cells take in more glucose
4. Lowers blood sugar levels.

Question 17

Describe a reflex arc in 5 steps (e.g. hot stove)

Answer 17

1. Initial stimulus: Hot stove burns hand.
2. Sensory Neurons: Heat on skin triggers stimulus to the spinal cord
3. Interneurons: send the signal to the motor neurons
4. Motor Neuron: activate the appropriate effector (muscles)
5. Effector Organ: Causes immediate response. (hand pulls back)

Question 18

Describe the process of action potential

Answer 18

1. Resting potential (-70)
2. Stimulus (-40)
3. De polarization (gates open)
4. Repolarization (gates close)
5. Refractory period

Question 19

What is action potential?

Answer 19

The way nerves communicate with each other.

Question 20

What is a reflex arc?

Answer 20

An action happening before the brain get the message.

This is possible because of the neural circuit that runs through the spinal cord.

Question 21

Synaptic Transmission

Answer 21

The way nerves communicate with each other.

Question 22

What are the steps of action potential?

Answer 22

1. Depolarization
2. Repolarization
3. Refractory Period

Question 23

Depolarization

Answer 23

How action potential is formed. K+ high on the outside Na+ high on the inside.

Na+ gate channels opens, K+ channel closes.

Question 24

Repolarization

Answer 24

Polarity is restored.

Na+ channel closes. K+ channel opens again.

Question 25

Refractory Period

Answer 25

1-10 milliseconds required for the cell to become repolarized.

Question 26

How are Neurotransmitters related to Depolarization?

Answer 26

Neurotransmitter ACETYLCHOLINE opens the Na+ channel.

Question 27

How are presynaptic neurons related to Depolarization?

Answer 27

Depolarization enables the presynaptic neuron to transmit a message.

Question 28

How are postsynaptic neurons related to depolarization?

Answer 28

The postsynaptic neurons receive the message from the presynaptic neurons via neurotransmitters the cross the synaptic gap.

Question 29

How do enzymes trigger Repolarization?

Answer 29

The enzyme CHINESTERASE is released after the message is sent. It EATS acetylcholine, closing the Na+ channel.