Exam Questions

Question 1

Is this conclusion valid? Explain.

Answer 1

Yes, as it tested what it was supposed to test and based off the limited information provided, the variables were controlled.

Question 2

Describe the structure of the meninges.

Answer 2

They are three connective tissue membranes between the bone and spinal cord/brain - the dura mater, arachnoid mater and pia mater.

Question 3

Describe two problems that extreme heat and humidity could cause for individuals walking through a hot, humid jungle.

Answer 3

Heat – too hot enzymes denature and effect all body functions
Humidity – inability to sweat so heat builds up

Question 4

A reflex is classified as part of a human’s non-specific defence system. Explain the reasoning.

Answer 4

Protective reflexes protects the body from injury/infection. It forces foreign antigens out from the body so they cannot cause harm.

Question 5

Explain why the wrong thing to do is treat a mild fever.

Answer 5

The heat from fevers increase the rate of chemical reactions in the body, which in turn increases the rate of cell repair when fighting pathogens. If the fever is reduced, bacteria/viruses breed at a normal rate and the person can become very ill.

Question 6

Explain what has gone wrong in the body for a person with Type 1 diabetes to suffer from thirst.

Answer 6

Increased osmotic pressure causes fluid to come out of cells into the blood to balance water levels. The cells then trigger the brain saying they are dehydrated, so the brain triggers the thirst response.

Question 7

What body structures produce lysozymes?

Answer 7

Eye ducts, lungs, sweat and vagina fluids.

Question 8

Negative feedback occurs when the original stimuli is…

Answer 8

The initial stimuli is reversed

Question 9

Name and describe one of the mechanisms promoting heat loss.

Answer 9

Vasodilation. Increases diameter of blood vessels to bring the heat to the body surface to increase radiation.

Question 10

What are the two types of sample groups?

Answer 10

Experimental group and control group.

Question 11

Is a person with Type 1 or Type 2 diabetes is more likely to suffer from hypoglycemia? Why?

Answer 11

Type 1. Insulin injections may be too often or contain too much insulin which would cause the cells to take up too much glucose, dropping the blood sugar levels.

Question 12

Describe four ways the spinal cord is protected from injury.

Answer 12

Vertebral column provides a strong and flexible structure that can absorb impact and provide support while allowing for a range of motion.
Spinal Cord Meninges help cushion and protect the spinal cord.
Cerebrospinal Fluid (CSF) acts as a shock absorber, providing a cushion against sudden impacts and also provides a medium for the exchange of nutrients and waste products between the spinal cord and surrounding tissues.
Vertebral Ligaments and Muscles provide additional support and help stabilize the spine, reducing the risk of injury.

Question 13

What is the role of hyperpolarization of a nerve fibre?

Answer 13

Hyperpolarisation is when the membrane potential drops lower than the resting membrane potential due to the potassium gates remaining open longer than what is needed.
Results in a refractory period.
A stronger than normal stimulus would be required during this time to generate a new action potential/ensures that another action potential can not be generated.
This ensures that the impulse travels in one direction along the nerve fibre and also regulates the frequency of action potentials.

Question 14

Explain what an “all-or-none” response means.

Answer 14

The term “all-or-none” describes the phenomenon where a neuron fires an action potential with the same magnitude and duration regardless of the strength of the stimulus.

Question 15

Compare osmoreceptors and thermoreceptors.

Answer 15

Similarities: Both sensory receptors which respond to a change in the external environment. Both involved in maintaining homeostasis.
Differences: Detects a change in osmotic
pressure, detects a change in
temperature. Located within the
hypothalamus, found throughout the body
including the skin, internal
organs and hypothalamus

Question 16

Describe how amine (water soluble) hormones work at a cellular level.

Answer 16

Attach to cell membrane receptor, initiates secondary messenger. Causes a cascade of chemical reaction in the cytoplasm/Attach to effector proteins in the cytoplasm.
Alters cell activities/activates enzymes to cause a rapid but short lasting effect.

Question 17

Nerve impulse across a synapse

Answer 17

1: Action potential arrives at axon terminal
2: Calcium ion channels open, causing an influx of calcium ions
3: Synaptic vesicles containing neurotransmitters move to the presynaptic membrane
4: Release of the neurotransmitters via exocytosis into the synaptic cleft
5: Neurotransmitters diffuse across synaptic cleft and bind with receptor on postsynaptic membrane.
6: Sodium gates open and if threshold is reached, action potential starts
7: Neurotransmitters in synaptic cleft are then destroyed

Question 18

Tolerance Limits

Answer 18

The limit of factors such as temperature and fluid balance beyond which the body malfunctions.

Question 19

Set point

Answer 19

In a feedback system, the level which a variable may be contained.

Question 20

Dynamic Equilibrium

Answer 20

A state reached when the rates of forward and reverse changes are equal - stable, balanced or unchanging system results.

Question 21

Describe four functions of growth hormone on the body.

Answer 21

Bone growth, muscle growth, increases blood concentration of glucose/fatty acids, increases amino acid uptake.

Question 22

Effect of sympathetic division on heart, blood vessels, salivary glands and sweat glands.

Answer 22

Increases heart rate and force, causes vasoconstriction, decreases saliva secretion and increases sweat secretion.

Question 23

Effect of parasympathetic division on heart, blood vessels, salivary glands and sweat glands.

Answer 23

Decreases heart rate and force, no effect on blood vessels, increases saliva secretion and no effect on sweat glands.

Question 24

Name the process that would be inactivated if the voltage-gated sodium channels are blocked during synapse transmission, and explain why the post-synaptic knob would not have been stimulated.

Answer 24

Action potential. The sodium ions remain on the outside of the cell and the potassium ions remain on the inside of the cell, leaving the cell polarised. The polarised cell cannot stimulate the cells of the memory centre / cannot cause an action potential to occur / cannot stimulate the neurons.

Question 25

Name the protective reflex that occurs as a result of anaphylactic shock and describe how it occurs.

Answer 25

Vomiting. Contraction of the muscles of the abdomen and diaphragm that expels the stomach contents.

Question 26

State how the adrenaline would make breathing easier and increase the blood pressure.

Answer 26

Adrenaline dilates bronchioles to allow more air into the lungs. Adrenaline causes vasoconstriction of blood vessels in the skin / vasodilation of the blood vessels to the heart / lungs OR increases heart rate which increases blood pressure.

Question 27

Explain how breathing into a paper bag prevents someone from losing consciousness when hyperventilating and allows them to regain control over their breathing rate.

Answer 27

Paper bag allows patient to breathe in CO2 again. CO2 levels rise, which lowers pH. Lower pH stimulates peripheral chemoreceptors/aortic and carotid bodies. Medulla oblongata/inspiratory centre triggered, breathing rate increased / regulated.

Question 28

Aldosterone

Answer 28

Aldosterone:
Secreted by adrenal cortex, acts on DCT and CT, increases reabsorption of sodium from tubules into blood and increases potassium ions secreted in urine through the sodium-potassium pump.

Question 29

Parathyroid hormone and calcitonin

Answer 29

Parathyroid hormone:
Secreted by parathyroids, targets bones, intestines and kidneys, increases calcium and phosphate levels in blood and increases bone reabsorption.
Calcitonin:
Secreted by thyroid gland, targets bones, decreases calcium and phosphate levels in blood by reducing calcium reabsorption by kidneys and breakdown of bone. Moves phosphate into bone, reduces kidney reabsorption.

Question 30

Spinal reflex properties

Answer 30

• A stimulus is required
• Involuntary
• Rapid
• Stereotyped

Question 31

Unmyelinated fibre transmission

Answer 31

Depolarisation of one area of the cell membrane causes an action potential to flow onto the membrane immediately adjacent to the stimulus. The nerve impulse/exchange of ions (NOT action
potential) moves along the entire length of the neuron/axon. The nerve impulse / message (NOT action potential) travels along the whole length of the fibre, reducing its speed.