Unit 4 - Exam Review

Question 1

7.1 Define Homeostasis

Answer 1

The physiological state of the body in which internal physical and chemical conditions are kept within a range that is suitable for life processes. For example – body temperature is 37˚C, blood pH 7.4 etc

Question 2

7.1 Define Dynamic Equilibrium

Answer 2

A condition that remains stable within fluctuating limits

Question 3

7.1 Negative feedback vs Positive feedback + Examples

Answer 3

+Process by which a small effect is amplified i.e. childbirth
-Process by which a mechanism is activated to restore conditions to their original state i.e. testosterone production

Question 4

7.2 Define Homeotherm, Poikilotherm, Endotherm, Ectotherm + Example

Answer 4

H - Organism that maintains a stable body temperature regardless of the temperature of the external environment; eg. Humans and birds.

P - Organism whos body temperature varies with, and often matches, the temperature of the external environment; eg. Reptiles, amphibians.

Endo - Organism that maintains its body temperature by internal mechanisms

Expo - Organism that maintains its body temperature by absorbing thermal energy from the environment

Question 5

7.2 Explain the body’s response to heat / cold

Answer 5

Hypothalamus sends signals to sweat glands to initiate sweating, evaporation on skin causes cooling, blood vessels dilate and blood loses heat to skin to cool internal organs

Hypothalamus sends signals to organs and tissues to increase body temp. Blood vessels constrict to prevent loss of heat to skin. Hair follicle muslces contract to cause goosebumps that trap warm air near skin. Shivering increases metabolism. Brown fat converts chemical energy to heat and is used when prolonged eposure to cold causes hormonal responses

Question 6

7.3 Define Deamination + Where it occurs

Answer 6

Removal of an amino group from an organic compound. Occurs in
liver

Question 7

7.3 Name 3 Products of Nitrogenous Waste + When they are released

Answer 7

Ammonia (released during deamination)
Uric acid (released during breakdown of nucleic acids)
Urea (formed by 2 ammonia and carbon dioxide as a way to remove ammonia from the body)

Question 8

7.4 Explain the Pathway of the Human Urinary System (parts + functions)

Answer 8

Kidney produces urine, ureter transports urine, bladder stores urine, urethera exports urine

Question 9

7.5 Explain the Pathway of the Formation of Urine (parts + functions)

Answer 9

Kidneys -> nephrons -> bowmans capsule -> glomerulous (filtration) -> proximal convoluted tubule (salts reabsorbed) -> descending loop on henle (water reabsorbed) -> ascending loop of henle (solutes reabsorbed) -> distil convoluted tubule (solutes reabsorbed, secretion) -> collecting duct -> ureter

Question 10

7.6 Name + Explain 3 functions of kidneys

Answer 10

Water Balance - ADH makes the walls of the distal tubule and collecting ducts more permeable to H2O

Blood PSI - Aldosterone increases N+ and H2O absorption, lowering psi. This triggers Renin to produce Angiotensin to constrict the blood vessels.

pH Balance - Bicarbonate-carbon dioxide buffer system, excess H+ are absorbed by bicarbonate ions

Question 11

7.7 (Kidney Disease) Explain Diabetes Mellitus, Diabetes Insipidus

Answer 11

Low insulin, high blood sugar, reverse osmotic psi, excess sugar in nephron causes water to stay in the nephron and gets lost in urine.

No ADH producing cells, no regulation of water reabsorption, lots of urine (and water) released

Question 12

7.7 (Kidney Disease) Explain Bright’s, Kidney Stones, Kidney Transplant + Body’s reaction

Answer 12

Inflamed nephrons, permeability of nephron affected, large molecules can enter the nephron (no mechanism designed to reabsorb), proteins stuck in nephron cause water to flow into the nephron and increases urine output

Caused by the precipitation of mineral solutes from the blood. The sharp-sided stones can lodge in the renal pelvis or move into the narrow ureter.

A new kidney and ureter are placed into the lower abdomen and surgically attached, the old kidney is only removed if it is infected, and a catheter is inserted to drain urine for the first few days. The immune system will usually attack the new kidney and this is they only downside.

Question 13

8.1 Define Hormones

Answer 13

Chemical messengers produced by cells in one part of the body (i.e ovaries) that effect cells of another part of the body (i.e breasts).

Question 14

8.1 Steroid vs Protein hormones (structure, receptor location, hydro-,example)

Answer 14

Steroid vs Protein
4 carbon rings cholesterol / 2-300 amino acid proteins
Nuclear membrane / Cell membrane
Hydrophobic / Hydrophilic
Sex hormones / Growth hormones

Question 15

8.1 Hypothalamus and pituitary function

Answer 15

The brain monitors bodys internal environment and regulates pituitary gland. Together they control many processes that maintain homeostasis. Hypothalamus secretes releasing factors into the pituitary gland.

Question 16

8.2 Explain Glucose Regulation + Hormones and what cells they are released by

Answer 16

Insulin - helps High Blood Sugar (produced by beta cells, released when blood sugar increases, causes cells of muscles, liver, and other organs to become permeable to glucose, In the liver glucose is converted into glycogen, the storage form of glucose)

Glucagon - helps Low Blood Sugar (produced by alpha cells, released when blood sugar decreases. Goes to the liver and forces glycogen to become glucose)

Question 17

8.4 2 Adrenal glands + Use + Hormones produced

Answer 17

Adrenal Medulla Short term stress - Epinephrine (adrenaline) and Norepinephrine (noradrenaline)

Adrenal Cortex Long term stress - Glucocorticoids: associated with blood glucose levels (cortisol), Mineralocorticoids (Aldosterone), Sex hormones

Question 18

8.3 Thyroid gland + Hormones produced

Answer 18

A two-lobed gland at the base of the neck that regulates the rate of glucose oxidation and lowers calcium in the blood.

produces thyroxine and triiodothyronine, and calcitonin

Question 19

8.3 Parathyroid glands + Hormones produced

Answer 19

four pea-sized glands in the thyroid gland that increase calcium in the blood.

produces parathyroid hormone

Question 20

8.3 (Thyroid Disorder) Explain goiter thyroidism, hyperthyroidism, hypothyroidism

Answer 20

Low iodine in the diet lowers thyroid production and secretion of thyroxine drops. This causes more TSH to be produced and the thyroid is stimulated more; thyroid cells continue to develop resulting in an enlarged thyroid.

Overproduction of thyroxine by the thyroid gland, the fast oxidation of nutrients causes weight loss, elevated body temperature, and nervous behaviour. The most common cause of hyperthyroidism is an inherited disorder known as Graves’ disease, or thyrotoxicosis.

Underproduction of thyroxine causes slowed body movements

Question 21

8.3 (Growth Disorder) Explain gigantism, dwarfism, acromegaly

Answer 21

high GH secretion during childhood, bone size increase

low GH secretion during childhood, inhibit development of bones

if GH production occurs after cartilaginous growth plates have fused, long bones cannot increase in length; however, width of forehead, fingers, and toes increase.

Question 22

8.4 Reaction to stress, explain Hans Selye’s General Adaptation Syndrome

Answer 22

Alarm (body mounts fight or flight response)

Resistance (Body attempts to deal with stress. If stress stops the body normalizes. If not the body adapts at a cost)

Exhaustion (The body’s resources are depleted, body function is impaired, sometimes death)

Question 23

8.5 Explain 2 Male Reproductive Hormone System Cycles + Initiation

Answer 23

At puberty, the hypothalmus secretes gonadotropic releasing hormone (GnRH) which causes the anterior pituitary to release FSH and LH.

LH stimulates interstitial cells -> increases testosterone -> increases sperm production -> inhibits anterior pituitary and hypothalmus -> inhibits LH release

FSH stimulates seminiferous tubules -> produces sperm -> sperm producing cells release inhibin -> inhibits anterior pituitary and hypothalmus -> inhibits FSH release

Question 24

8.5 Female Reproductive System (Ovarian cycle)

Answer 24

Flow Phase - day 1
Low progesterone causes GnRH released by hypothalamus -> GnRH stimulates the pituitary to release FSH -> FSH stimulates the ovaries to release estrogen and mature egg -> estrogen stimulates uterus to thicken the lining

Follicular Phase - day 6
High estrogen levels -> inhibit FSH -> stimulates LH

Ovulation - day 14
LH stimulates ovulation (release of egg)

Luteal Phase - day 28
The released egg travels to oviduct -> Follicle that egg is released from becomes corpus luteum -> produces progesterone ->
1. if fertilization occurs progesterone remains high (stops cycle) ->
inhibits LH and FSH
2. If fertilization doesnt occur, egg released will pass out uterus lining and estrogen/progesterone will stop production

Question 25

9.1 CNS vs PNS

Answer 25

CNS: the body’s coordinating centre for mechanical and chemical actions; made up of the brain and spinal cord

PNS: all parts of the nervous system, excluding brain and spinal cord, that relay information between the central nervous system and other parts of the body

Question 26

9.1 Define - glial cells, neurons, sensory neurons, ganglia, motor neurons, dendrites, axon, myelin sheath, Schwann cells, nodes of Ranvier, neurilemma, reflex arc

Answer 26

glial cells: non conducting cells important for structural support and metabolism of the nerve cells
neurons: nerve cells that conduct nerve impulses
sensory neurons: neurons that carry impulses from sensory recep- tors to the central nervous system; also known as afferent neurons
ganglia: collections of nerve cell bodies located outside of the central nervous system
motor neurons: neurons that carry impulses from the central nervous system to effectors; also known as efferent neurons
dendrites: projections of cytoplasm that carry impulses toward the cell body
axon: extension of cytoplasm that carries nerve impulses away from the cell body
myelin sheath: insulated covering over the axon of a nerve cell
schwann cells: special type of glial cell that produces the myelin sheath
nodes of Ranvier: regularly occur- ring gaps between sections of myelin sheath along the axon
neurilemma: delicate membrane that surrounds the axon of some nerve cell
reflex arc: neural circuit through the spinal cord that provides a framework for a reflex action

Question 27

9.1 Grey matter vs white matter

Answer 27

Grey matter - Butterfly core, cell bodies and dendrites
White matter - Surrounds grey matter, consists of axons

Question 28

9.3 Define - meninges, cerebrospinal fluid, meningitis

Answer 28

m - three layers of connective tissue that protect the brain and spinal cord
cf - fluid that circulates around membranes of the brain and spinal cord cushioning, nourishing, and protecting them from toxic substances. It also provides neural connection to the endocrine system.
m - meningitis is an inflammation (swelling) of the protective membranes covering the brain and spinal cord

Question 29

9.3 Basic structure of the spinal cord and function

Answer 29

Extends from the base of the brain down through a canal inside the vertebrae of the backbone. Carries impulses from the brain and PNS. Contains interneurons that control motor reflexes.

Question 30

9.3 The Brain: 3 regions and the corresponding structures found in each, basic function of these parts

Answer 30

Forebrain - Two hemispheres, senses and thought. Cerebrum

Midbrain - Consists of grey matter, used for some eye and ear movements

Hindbrain - Connection between the spinal cord and the brain, the most primitive part of the brain. Controls most basic life activities. All sensory and motor information passes through it as a filter that selects which information reaches higher brain centers
1. Cerebellum 2. Pons 3. Medulla Oblongata

Question 31

9.3 Lobes of the cerebrum

Answer 31

1. Frontal Lobe: Voluntary muscle (walking, speech), personality
2. Temporal Lobe: Vision and hearing, memory, interpreting sensory information
3. Parietal Lobe: Touch and temperature, emotion and interpreting speech
4. Occipital Lobe: Vision and interpreting visual information

Question 32

9.2 Known the stages of the AP, and the resulting graph produced

Answer 32

1) At rest, the outside of the neuron is more positive than the inside. More Na+ outside and more K+ inside.

2) Electrical impulse moves across cell membrane which opens Na+ channels

3) Na+ rushes in making the inside more positive resulting in an ACTION POTENTIAL. The membrane is depolarized.

4) Depolarization causes Na+ gated channels to close while K+ gated channels open. K+ flows out of the membrane down the gradient by diffusion which restores the resting potential (outside more +ve)

5) Then all gated channels close and the Na+/K+ pump takes over to restore resting potential. The adjacent section of axon is stimulated and the process repeats as the action potential travels down the axon.

Question 33

9.2 Define - synapses, neurotransmitters, presynaptic and postsynaptic neurons

Answer 33

synapses: space between neurons
neurotransmitters: chemical messengers
presynaptic: transmits signal toward synapses
postsynaptic: transmits signal away from synapses