Homeostasis

Question 1

Definition of homeostasis

Answer 1

Ability of an organism to maintain its internal environment despite changes to its internal or external environment.

Question 2

What is most disease caused by?

Answer 2

Homeostatic imbalance

Question 3

What factors can cause homeostatic imbalance?

Answer 3

Aging
Genetic mutation
Pathogens
Environmental factors
Stress

Question 4

What is the name for any stimulus that creates an imbalance in the INTERNAL environment?

Answer 4

Stress

Question 5

Homeostatic pathway

Answer 5

Stimulus > receptor (afferent path) > control center > efferent path > effector > response

Question 6

A decrease in BP can trigger what type of response to restore homeostasis?

Answer 6

Both neural (baroreceptor) and endocrine (RAAS)

Question 7

Cell signaling in which chemicals secreted from a cell work on that same cell.

Answer 7

Autocrine

Question 8

Cell signaling in which chemicals work on an adjacent cell.

Answer 8

Paracrine

Question 9

Lipid soluble hormones bind to…

Answer 9

receptors on nucleus (are able to diffuse into cell)

Question 10

Water soluble hormones bind to…

Answer 10

Cell surface receptors (GPCR)

Question 11

Example of an imbalance in endocrine cell signaling

Answer 11

Elevated TSH

Question 12

Example of an imbalance in neuronal cell signaling

Answer 12

Hyper/hypostimulation of post synaptic membrane in muscle synapse

Question 13

What type of receptor regulation triggers a decrease in the number of receptors in the presence of a hormone, and causes the cells to become less sensitive?

Answer 13

Down-regulation

Question 14

What type of receptor regulation triggers an increase in the number of receptors in the absence of a hormone, and makes cells more sensitive?

Answer 14

Up-regulation

Question 15

What action does the response of the system have on the receptor in negative feedback?

Answer 15

Response is fed back to the receptor and cancels or counteracts the effect of the original stimulus

Question 16

Which type of feedback mechanism is the most common?

Answer 16

Negative feedback (body senses change, activates mechanisms to reverse change)

Question 17

Which feedback process is self-amplifying, where physiological change leads to even greater change in the same direction?

Answer 17

Positive feedback

Question 18

Regulation of BP is an example of which type of feedback?

Answer 18

Negative

Question 19

Example of a positive feedback system

Answer 19

Parturition. Stretch receptors in the uterus cause release of oxytocin and increasing muscle contraction until the fetus is expelled.

Question 20

Aging and overwhelmed negative feedback systems can lead to…

Answer 20

Heart failure. Positive feedback mechanisms take over.