B10 Homestasis And Nervous System

Question 1

What is Homeostasis?

Answer 1

Homoeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.

Question 2

What body parts are involved with Homeostasis?

Answer 2

-Kidneys:
Regulate water & mineral salts (ion) concentration

• Skin :
  Regulate body temperature

-Liver & pancreas :
Regulate blood glucose level

Question 3

Give an example of homeostasis in humans?

Answer 3

Maintaining blood glucose levels

Question 4

Why is homeostasis important?

Answer 4

-Homeostasis is important as the body needs to have a constant internal environment in order for it to be functioning at an optimum level.

Question 5

What is thermal regulation?

Answer 5

Thermoregulation is the control of body’s internal temperature.It involves the hypothalamus detecting changes in the temperature of the blood flowing around it. If the blood is too warm it can either cause vasodilation or stimulate sweat glands. While if its too cold it can stimulate muscles to lift hair ( traps air) , vasoconstriction or shivering.

Question 6

What is the hypothalamus?

Answer 6

• The hypothalamus is the part of the brain which monitors the body’s temperature.
• it receives information from temperature-sensitive receptors in the skin and circulatory system.

Question 7

What is vasodilation?

Answer 7

• Vasodilation is a response to being too hot.
• The process includes the widening of blood vessels at the skin surface to increase heat loss through the surface of skin.

Question 8

What is vasoconstriction?

Answer 8

• Vasoconstriction is a response to being too cold.
• The process involves the narrowing of blood vessels at the skin surface to reduce heat loss through the surface of the skin.

Question 9

What is body temperature?

Answer 9

The average temperature in the body which satisfies all reactions and enzymes allowing them to function at an optimum level.

Question 10

Why does this temperature need to be maintained?

Answer 10

Body temperature needs to be maintained because chemical reactions and enzymes need to be functioning at an optimum level to keep the body alive. If the body temperature wasn’t regulated then enzymes may denature or slow down. Or respiration may not happen fast enough.

Question 11

What changes occur when you are too hot?

Answer 11

-When you too hot your blood temperature raises.
-This hot blood is then flowing next your hypothalamus which detects this change in temperature.
-The Hypothalamus then sends an electrical impulse to your skin. The impulse stimulus your sweat glands to secret sweat.
-The sweat then evaporates of your skin. When the sweat evaporates it causes internal energy to be lost ( in the form of heat ) to the surrounding from your body. This results in your body cooling down. a
Additionally, it stimulates vasodilation.

Question 12

What changes occurs when you are too cold?

Answer 12

• Muscles shiver to warm up

- Hair stands up to trap air to insulate heat.

Question 13

Why is thermoregulation described as a negative feedback loop?

Answer 13

Both cooling and heating work at the same time this creates a constant environment as both functions work against each other, keeping the temperature of the body constant.

Question 14

What are the key features a control system in the body needs?

Answer 14

• receptors
• coordination centres
• Effectors

Question 15

What are receptors?

Answer 15

Cells that detect changes in the internal or external environment. These changes are known as stimuli. Receptors may be part of the nervous or the hormonal control systems of the body.

Question 16

What is are coordination centres?

Answer 16

Areas that receive and process the information from the receptors. They send out signals and coordinate the response of the body. They include the brain, which is as coordination Centre from both the nervous system and plight of the rotor system, the spinal-cord, and some organs such as the pancreas.

Question 17

What are effectors?

Answer 17

Muscles or glands that bring about a response to the stimulus that has been received. These response restore conditions in the body to the optimum levels.

Question 18

What are the internal conditions that are controlled?

Answer 18

• body temperature
• The water content of the body
• blood glucose concentration

Question 19

What is Stimulus

Answer 19

Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli.

Question 20

What are neurones?

Answer 20

Once a sensory receptors detect a stimulus, the information is sent as an electrical impulse passes along special cells called neurones.

Question 21

What are nerves?

Answer 21

A bundle of neurones is called a nerve.

Question 22

What is the central nervous system(CNS)?

Answer 22

The part of the nervous system made up of the brain and spinal cord.

Question 23

What are the functions of the central nervous system?

Answer 23

• To process sensory information. The CNS receives electrical impulses from sensory neurons connected to the sense organs.
• To coordinate the body’s response. The CNS transmits electrical impulses, along motor neurons, to glands and muscles.

Question 24

What are sensory neurones?

Answer 24

A neuron that carries an electrical impulse from receptor at wards the central nervous system

Question 25

What are motor neurones?

Answer 25

A neuron that carries an electrical impulse away from the central nervous system to an effector( muscle or gland)

Question 26

What is a receptor?

Answer 26

A cell or group of cells at the beginning of a pathway of neurons that the detects a change and generate an electrical impulse.

Question 27

What is are effectors?

Answer 27

an organ or cell that acts in response to a stimulus.

Question 28

How does your control system work in homeostasis?

Answer 28

Receptors -> Coordination Centres -> Effectors

Question 29

How do you sum up the nervous system?

Answer 29

Stimulus -> receptor -> Coordinator (CNS) -> Effector

Question 30

What is the difference between the structure of the sensory and motor neurones?

Answer 30

• Sensory nerves carry impulses to the CNS.
• Neurone ending for Sensory Neurone is the central nervous system
• Sensory neurone has sensory receptor

Question 31

What are reflexes?

Answer 31

Reflexes are automatic and rapid actions and do not involve the conscious part of the brain.

Question 32

What is a reflex arc

Answer 32

The pathway of neurons in a relax actionh

Question 33

What is synapse?

Answer 33

A gap between the accident of one nerve dendrites of another where chemical neurotransmitters transmit the impulses.

Question 34

What are dendrites?

Answer 34

The bronzed beginnings of neurons, which can detect chemical neurotransmitters and start another electrical impulse.

Question 35

What are the main stages of a reflex arc?

Answer 35

Stimulus -> receptor -> sensory neurone -> relay neurone -> motor neurone -> effector -> response.

Question 36

What is myelin sheath?

Answer 36

The myelin sheath is a fatty layer that surrounds the axon. The sheath acts as an insulator and speeds up nerve impulses. The branched ends of the axon and the smaller branches coming from the cell body allow the neurone to make connections with many other neurones.

Question 37

What is a reflex action?

Answer 37

Reflex actions are rapid , automatic responses to a stimulus to protect the body from harm

Question 38

How does the impulse cross the gap between neurones

Answer 38

• The nerve impulse causes vesicles to move to the edge of synapse space where
• neurotransmitters are released into the synaptic space where the diffuse across and bind to the receptors in the next nerve
• the receptors generate a new nerve impulse