Holding It All Together - Control, Communication and Protection

Question 1

Central Nervous System

Answer 1

• Brain and spinal cord

- Combines information from the entire body and coordinates activity across the whole organism

Question 2

Peripheral Nervous System

Answer 2

• Outside brain and spinal cord
• Spinal nerves and cranial nerves
• VOLUNTARY (SOMATIC):
  > Sensory neurons carry info. from nerves to CNS
  > Motor neurons carry info. from CNS to muscle fibres throughout the body
• INVOLUNTARY (AUTONOMIC):
  > Sympathetic - mobilises
  > Parasympathetic - counteracts

Question 3

Neurons

Answer 3

• Info. travels in one direction from cell body to axon terminal
• Produce electrical impulses
• A nerve is a bundle of individual neurons

Question 4

Voluntary Functions

Answer 4

Skeletal muscles

Question 5

Involuntary Functions

Answer 5

• Smooth and cardiac muscles

- E.g. heart rate, digestion, pupillary response, etc.

Question 6

Autonomic Nervous System

Answer 6

• Sympathetic = fight or flight response

- Parasympathetic = rest and restore

Question 7

Endocrine System

Answer 7

• Hormones released into the blood
• Slower but longer lasting
• “Ductless”

Question 8

Thyroid Hormone

Answer 8

• Increases basal metabolic rate

- Cells start working harder which causes an increase in the heat our cells produce (thermoregulation)

Question 9

Thyroid Problems: Too Much

Answer 9

• Hyperthyroidism
• Heat intolerance
• Tachycardia
• Raised BP
• Weight loss
• Muscle tremors

Question 10

Thyroid Problems: Too Little

Answer 10

• Hypothyroidism
• Cold intolerance
• Lethargic
• Bradycardic
• Weight gain
• Dry, scaly skin

Question 11

Insulin

Answer 11

• Modulates blood glucose (normal: 4-6mmol)
• Secreted by beta cells as a response to an increase in blood glucose level
• Causes liver, skeletal muscle and adipose tissue to uptake glucose into cell, used for energy or stored in the form of glycogen or fat

Question 12

Glucagon

Answer 12

• Stimulates release of glucose

- Secreted by alpha cells as a response to low blood glucose

Question 13

Parathyroid Hormone

Answer 13

• Modulates calcium and phosphorus concentration
• Secreted in response to decrease in plasma calcium level
• Calcium removed from bone into bloodstream; calcium excretion by kidney is reduced; Vitamin D production increased (more calcium absorbed by gut)

Question 14

Parathyroid Problems: Too Much

Answer 14

• Hyperparathyroidism
• Calcium deposits in the lungs
• Kidney stones
• “Salt and pepper skull”

Question 15

Parathyroid Problems: Too Little

Answer 15

• Hypoparathyroidism
• Caused by decreased calcium in the blood, a result of hypoparathyroidism:
  > Convulsions
  > Arrhythmias
  > Tetany
  > Spasms and stridor

Question 16

Cortisol

Answer 16

• Released in times of stress
• Adrenal cortex
• Steroid-based hormone
• It:
  > Increases blood glucose
  > Increases blood lipids
  > Suppresses immune response
  > Inhibits growth and repair

Question 17

Cortisol Problems: Too Much

Answer 17

• Cushing’s Disease
• Moon face
• High BP and enlarged heart
• Muscle weakness and osteoporosis
• Increase in fat deposition

Question 18

Cortisol Problems: Too Little

Answer 18

• Adrenal Insufficiency or “Addison’s Disease”
• Bronze pigmentation
• Hypoglycaemia
• Weight loss
• Weakness

Question 19

Aldosterone

Answer 19

• Steroid-based hormone
• Modulates BP
• Main role is to increase retention of sodium, therefore, increasing BP
• Adrenal cortex

Question 20

Aldosterone Problems: Too Much

Answer 20

• Hypertension: increase in BP due to increase in BV

- Retaining sodium in the plasma, osmotic pull on water increasing BV

Question 21

Aldosterone Problems: Too Little

Answer 21

• Decrease in amount of sodium in blood meaning water will most likely follow it
• Hypotension: decrease in BV meaning a decrease in BP
• Possibly dehydration as BV is dropping

Question 22

Adrenaline

Answer 22

• Adrenal gland from medulla
• Amine
• Released into the bloodstream, causes a hormonal extension of the sympathetic response
• Produces responses of sympathetic activation - increase HR, vasoconstriction/dilation and bronchodilation

Question 23

Sex Hormones: Female

Answer 23

• Oestrogen:
  > Maintenance of many tissues, menstrual cycle regulation, secondary sex characteristics, metabolic effects
• Progesterone:
  > Release of eggs from ovary, implantation, maintenance of pregnancy

Question 24

Sex Hormones: Male

Answer 24

• Testosterone:
  > Responsible for maturation and maintenance of the male sex organs, sperm production and secondary sex characteristics

Question 25

Growth Hormone

Answer 25

• Stimulates growth in many tissues
• Increases height (long bone growth), bone density, muscle mass and mobilises glucose and fats into the bloodstream
• Plays an important role in maintaining some tissues in later life

Question 26

Growth Hormone Problems

Answer 26

• GH secretion at its maximum during puberty
• Insufficient GH = dwarfism
• To much = gigantism

Question 27

Oxytocin

Answer 27

• Causes powerful uterine contractions during labour
• Causes milk let-down during suckling
• Important in social and pair bonding, and reduces social stress

Question 28

Anti-Diuretic Hormone (ADH)

Answer 28

• Reduces diuresis (reduction in the urine output)
• Released by neurons in the hypothalamus, axons project to the posterior pituitary
• Increased release of ADH with increased osmolarity of the plasma - detected by specialised receptors in the brain
• Reduce the amount of water lost in urine - helps to maintain solute concentration (osmolarity) of body fluids within normal limits

Question 29

ADH Problems: Too Much

Answer 29

• Really concentrated urine - retaining so much water

- Hyponatraemia - retaining so much water that the sodium in our blood is diluted

Question 30

ADH Problems: Too Little

Answer 30

• Lose a lot of water

- Thirsty as there is lots of water lost in urine