HOMEOSTASIS

Question 1

Define the term homeostasis

Answer 1

is the maintenance of a constant internal enviornment of the body.

Question 2

What are the two feedback mechanisms that moderate the processes in the body

Answer 2

Positive and Negative Feedback

Question 3

Explain what is meant by positive feedback

Answer 3

when a change is detected and the body responds by amplifying rhe change ( adds to the change). The change is amplified until the stimulus is removed.

Question 4

Explain what is meant by negative feedback

Answer 4

When a change is detected the body responds by reversing the change that is detected (to reduce the change)

Question 5

What is a stimulus?

Answer 5

Is the change in the enviornment that causes a reaction in the body

Question 6

What is the sensory receptor

Answer 6

it detects or senses the change in the stimulus of physiological variable. This may be a cell, tissue or organ.

Question 7

What are the sense organs

Answer 7

eyes, ears, nose, tongue, and skin

Question 8

Examples of positive feedback

Question 9

What is the control centre and how does it work?

Answer 9

It determines what the normal levels should be in the body.

It recieves the message from the sensory receptor and sends the message to rhe parts of the body that needs to respond to return the levels back to normal

Question 10

Name the control centre

Answer 10

The Brain

Question 11

What does the effector do?

Answer 11

It responds to the message from the control centre and carries out the response to change the levels back to normal levels.

Question 12

Example of Negative feedback of blood glucose regulation( when its too high)

Answer 12

when the blood sugar (glucose) rises in the blood from normal levels, the cells in the pancreas, secrete insulin in response. This insulin sends a signal to the liver, muscles and other cells to take up the excess glucose from the blood and excess glucose.

Question 13

What does the liver and muscles store?

Answer 13

The liver and muscles store the excess glucose as glycogen.

Some of the excess glucose may be stored as body fat and the cells may also use it for energy.

Question 14

What occurs when the gluucose level is too low

Answer 14

When the blood glucose level is too low, the cells in the pancreas releases the hormone glucagon. Glucagon goes to the liver and causes the break-down of glycogen into glucose. The glucose enters the blood stream and glucose levels increase back to normal.

Question 15

What is Temperature regulation

Answer 15

how the body keeps its temperature constant.

The body is warmed by the blood which is receives heat from the liver. Externally the body is heated directly from the sun and hot foods and drinks.

Question 16

What is The Body’s Response In a Hot Environment?

Answer 16

1. Vasodilation - the blood vessels below the skin will dilate (widen) and flow close to the surface
2. Sweating - Sweat glands excrete more sweat so that a continuous layer of moisture covers the skin and is evaporated thus cooling the skin.

Question 17

What is The Body’s Response in a Cold Environmen

Answer 17

1. Vasoconstriction- the blood vessels near the skin will constrict (narrow) and the flow of blood to the surface is reduced to minimize heal loss. This causes the skin to look pale and blue.
2. No Sweating-The sweat glands do not excrete sweat hence the amount of sweat produced is reduced to prevent the cooling of the body that occurs when sweat evaporates. Also, the skin may become dry.
3. Shivering which is the slight uncontrollable shaking occurs in reaction to the individual being cold.