homeostasis

Question 1

negative feedback

2

Answer 1

• Primary mechanism of homeostasis
• A stimulus (from change in internal/external environment) triggers a response that will compensate that change to maintain equilibrium

Question 2

positive feedback

3

Answer 2

• A response of a system that acts to increase the effect of any changes made to the system
• Sets in motion a chain of events that intensify a change from an original condition
• Usually does not result in homeostasis; generally associated with system instability

Question 3

stimulus

Answer 3

Change internal/external environment

Question 4

sensor

Answer 4

located in the tissues and organs of the body. A signal is sent to the coordinating centre once an organ begins to operate beyond its normal limits

Question 5

integrator

Answer 5

control/processing centre that compares existing conditions to optimal functioning conditions

Question 6

effector

Answer 6

if the environmental condition is outside the set point, the effector makes a response to restore normal balance

Question 7

urine

Answer 7

Fluid consisting of water and waste (NH3) formed in the kidneys

Question 8

urine formation steps

Answer 8

filtration, reabsorption, secretion

Question 9

filtration (urine)

Answer 9

movement of fluids from the blood in the glomerulus to the Bowman’s capsule through a selectively permeable membrane.

Question 10

reabsorption (urine)

Answer 10

transfer of fluids from nephron into peritubular capillaries (return substances to the blood)

Question 11

secretion (urine)

Answer 11

transfer of fluids (wastes/toxins) from peritubular capillaries (blood) and interstitial fluid into nephron.

Question 12

deamination

Answer 12

• In situations of excess protein intake, deamination is used to break down amino acids for energy.
• The amino group is removed from the amino acid and converted to ammonia.
• Byproduct= NH3 (ammonia)

Question 13

pituitary gland

Answer 13

• Located within the cranium, just below the brain
• Referred to as the “master gland” because it produces and secretes hormones that control most other endocrine glands and some bodily processes

Question 14

two major lobes

Answer 14

anterior and posterior

Question 15

anterior lobe

Answer 15

• produces its own hormones
• secretion of hormones is controlled by hypothalamus producing releasing or inhibiting hormones (neurohormones)

Question 16

posterior lobe

Answer 16

stores and releases two hormones produced by the hypothalamus

Question 17

oxytocin

Answer 17

Oxytocin is involved in reproduction. It stimulates the release of milk from mammary glands for nursing mothers. During birth, the hormone acts on the uterine and promotes contractions.

Question 18

ADH( vasopressin)

Answer 18

Antidiuretic hormone (ADH) stimulates the kidney cells to absorb more water from the urine, which increases the volume of the blood. So, it controls the water reabsorption in the kidneys.

Question 19

neuron

Answer 19

Specialized nerve cell that is the functional unit of the nervous system allowing for an organism to receive and respond to internal and external stimuli

Question 20

cell body

Answer 20

• contains the nucleus
• synthesizes most of the neuron’s proteins, carbohydrates, and lipids

Question 21

dendrites

Answer 21

highly branches projection of cytosol that carries signals from outside the neuron toward the cell body

Question 22

axon

3

Answer 22

• an extension of cytosol that carries impulses away from the cell body and to another neuron or an effector
• usually branch at their tips that end in small button-like swellings called axon terminals
• form bundles that make up nerve fibres with connective tissue

Question 23

axon terminals

Answer 23

points if connection that enable signals to be transmitted from one neuron to another neuron or an effector

Question 24

schwann cells

Answer 24

a type of glial cell that wraps around the axon forming a myelin sheath

Question 25

myelin sheaths

Answer 25

electrical insulators due to theie high lipid content

Question 26

nodes of ranvier | 2

Answer 26

- the gaps between sections of myelin sheaths; axons are directly exposed to extracellular fluid - a combination of gaps and insulated portions speeds the rate at which electrical impulses move along the axons

Question 27

steps involving synaptic transmission using a neurotransmitter | 7

Answer 27

1. Impulse reaches the synapse from the axon. 2. Impulse stimulates synaptic vesicles to move to the presynaptic membrane. 3. Synaptic vesicles dump neurotransmitter substances into the synaptic cleft. 4. Neurotransmitter substance diffuses across the cleft. 5. Neurotransmitter substance fits into receptor sites on postsynaptic membranes. 6. An enzyme cleaves the neurotransmitter substance and clears out the synaptic cleft. 7. An action potential is stimulated at the postsynaptic membrane and impulse travels down dendrite.

Question 28

adrenal medulla | 2

Answer 28

- Regulated by nervous system - Adrenal medulla produces epinephrine (adrenaline) and norepinephrine

Question 29

epinephrine | 4

Answer 29

- glycogen breakdown into glucose -> increases blood sugar level and results in a sudden burst of energy - increases heart rate and respiratory rate and cell metabolism - vasodilation -> increases blood supply oxygen and nutrients to tissues (i.e., muscle) - retinal dilation -> enhanced visual perception

Question 30

norepinephrine | 2

Answer 30

- has the same effects as epinephrine, also increases blood pressure - affects the amygdala – an attention centre in the brain

Question 31

function of adrenaline

Answer 31

Adrenaline (epinephrine) is a hormone your adrenal glands make to help you prepare for stressful or dangerous situations. Adrenaline rush is the name for the quick release of adrenaline into your bloodstream. This gets your body ready for a “fight or flight” response.