EMPA

Question 1

What does the autonomic nervous system do?

Answer 1

Controls and regulates the involuntary activities of internal muscles and glands

Question 2

What are the two divisions of the autonomic nervous system?

Answer 2

1. Sympathetic nervous system

2. Parasympathetic nervous system

Question 3

What 3 things does the sympathetic nervous system do?

Answer 3

1. Stimulates effectors to speed activity up
2. Acts like an emergency controller when we exercise strenuously
3. Heightens awareness, preparing for the fight or flight response

Question 4

What 3 things does the parasympathetic nervous system do?

Answer 4

1. Inhibits effectors, so slows down activity
2. Controls activity under normal resting conditions
3. Conserves energy and replenishes the reserves

Question 5

What are changes to the heart rate controlled by?

Answer 5

The region of the brain called the medulla oblongata

Question 6

What are the two centres of the medulla oblongata?

Answer 6

1. A centre that increases heart rate, linked to the sinoatrial node by the sympathetic nervous system
2. A centre that decreases heart rate, linked to the sinoatrial node by the parasympathetic nervous system

Question 7

Where are chemoreceptors found?

Answer 7

In the wall of the carotid arteries which serve the brain

Question 8

What are chemoreceptors sensitive to?

Answer 8

Changes in the pH of the blood that result from changes in carbon dioxide concentration. In solution, carbon dioxed forms an acid and lowers pH

Question 9

Describe in 5 steps the control by chemoreceptors?

Answer 9

1. When blood has high carbon dioxide levels, pH is lowered
2. Chemoreceptors in cartorid arteries and aorta detect this and increase nervous impulses to medulla oblongata
3. The centre increases impulses via sympathetic nervous system to sinoatrial node to increase heart rate
4. Increased blood flow leads to more carbon dioxide being removed by lungs, so level in blood returns to normal
5. Medulla oblongata reduces impulses to sinoatrial node, decreasing heart rate to normal

Question 10

What 2 things do the pressure receptors do when blood pressure is higher than normal?

Answer 10

1. They transmit a nervous impulse to the centre in the medulla oblongata to decrease heart rate
2. This sends impulses via parasympathetic nervous system to sinoatrial node of the heart to decrease heart rate

Question 11

What 2 things do the pressure receptors do when blood pressure is lower than normal?

Answer 11

1. Transmit a nervous impulse to centre in medulla oblongata to increase heart rate
2. This centre sends impulses via sympathetic nervous system to sinoatrial node to increase heart rate

Question 12

What is the test to see if carbon dioxide is present?

Answer 12

Limewater test

Question 13

What is the null hypothesis?

Answer 13

No difference between the amount of carbon dioxide and holding breath

Question 14

What is homeostasis?

Answer 14

The maintenance of a constant internal environment

Question 15

What 3 things is it important for homeostasis to maintain?

Answer 15

1. Temperature
2. pH
3. Glucose

Question 16

What do homeostatic systems respond by when they detect a change?

Answer 16

Negative feedback

Question 17

What three things do homeostatic systems involve?

Answer 17

1. Receptors
2. Communication system
3. Effectors

Question 18

What do receptors and effectors do in homeostasis?

Answer 18

Receptors detect when a level is too high or low and the information is communicated via the nervous or hormonal system

Effectors counteract the change to bring the level back to normal

Question 19

In homeostasis, what is negative feedback?

Answer 19

Mechanism that restores the level to normal

Question 20

What happens to enzymes if blood pH is too high or low?

Answer 20

They become denatured

Question 21

Why does homeostasis involve multiple negative feedback systems?

Answer 21

Gives it more control over changes in internal environment to increase or decrease a level to return it to normal

Question 22

Describe what happens during positive feedback?

Answer 22

Effectors respond to further increase the level away from its normal level

Question 23

In 3 steps, what happens to enzymes if blood pH is too high or low?

Answer 23

1. They become denatured
2. So, hydrogen bonds are affected, changing shape of active site, so it longer works as a catalyst
3. Metabolic reactions are less effective

Question 24

What do some changes, such as Hypothermia or a injury trigger?

Answer 24

Positive feedback system

Question 25

Describe what happens during positive feedback?

Answer 25

Effectors respond to further increase the level away from its normal level

Question 26

What is the optimum pH for an enzyme

Answer 26

pH 7

Question 27

What controls body temperature in mammals?

Answer 27

The part of the brain called the hypothalamus

Question 28

What is the concentration of glucose in the blood normally at?

Answer 28

90 mg per 100 cm(3 cubed)

Question 29

What are animals either classed as depending on how they control their body temperature?

Answer 29

Ecotherms - can't control body temperature internally, so have to do it by behaviour such as reptiles basking in sun/ sitting in shade Endotherms - can control body temperature by homeostasis or behaviour

Question 30

What and where does the hypothalamus receive information from?

Answer 30

Receives information about internal and external temperatures from the thermoreceptors

Question 31

Name the 5 organs of the human gas exchange system?

Answer 31

1. Trachea 2. Bronchi 3. Bronchioles 4. Alveolus 5. Diaphragm

Question 32

Describe what happens in 6 steps during inspiration?

Answer 32

1. Diaphragm contracts and flattens 2. External intercostal muscles contract 3. Ribs move upwards and outwards 4. Thorax cavity volume increases 5. Pressure in lungs decreases 6. Air moves into lungs

Question 33

Describe in 6 steps what happens during expiration?

Answer 33

1. Diaphragm relaxes and domes 2. External intercostal muscles relax 3. Ribs move down and inwards 4. Thorax cavity volume decreases 5. Pressure in lungs increases 6. Air is forced out of the lungs

Question 34

Give 4 ways the alveoli is efficient gas exchange?

Answer 34

1. Alveoli epithelium and capillary endothelium wall are thin with a single layer of cells = short diffusion pathway 2. Large number of alveoli and pulmonary capillaries = large surface area 3. Ventilation and circulation = maintained concentration gradient 4. = Fast diffusion

Question 35

Name 4 diseases of the lungs?

Answer 35

1. Emphysema 2. Tuberculosis 3. Asthma 4. Fibrosis

Question 36

In 9 steps, explain what happens during tuberculosis?

Answer 36

1. Bacteria transmitted in droplets, such as sneezing and coughing 2. Bacteria engulfed by phagocytes 3. Bacteria encased in tubercle in wall of lungs 4. Bacteria is dormant and not replicating 5. If immunosuppressed, bacteria is activated and replicates 6. Bacteria destroys alveoli 7. Leading to scar tissue and fibrosis 8. Damage leads to less diffusion, surface area and increases distance 9. Damage allows bacteria to enter blood, spreading to other organs

Question 37

Explain in 7 steps what happens during emphysema?

Answer 37

1. Alveoli beak down 2. Less surface area, increased diffusion distance 3. Loss of elastin, so reduced elasticity 4. Lungs cannot expand and recoil 5. Reduced diffusion gradient 6. Less oxygen enters blood 7. Less respiration and less ATP produced

Question 38

Explain in 5 steps what happens in fibrosis?

Answer 38

1. Scar tissues form on epithelium on lungs 2. Alveolar walls thicken 3. Longer diffusion pathway 4. Scarred tissue reduces surface area 5. Reduced elasticity to expand and recoil, effecting respiration

Question 39

Describe in 4 steps what happens with asthma?

Answer 39

1. Asthma is the irritation and inflammation of airways 2. Epithelial cells secrete large quantities of mucus 3. Fluid leaves capillaries and enters airways 4. Smooth muscle in bronchioles contracts and constricts airways