Intro Lecture

Question 1

Cell Communication
“Talk to yourself”

Answer 1

Autocrine

Question 2

Cell Communication
“Talk to your neighbors”

Answer 2

Paracrine & Cell Junctions

Question 3

Cell Communication
“Talk long distance rapidly”

Answer 3

Nervous

Question 4

Cell Communication
“Talk long distance gradually”

Answer 4

Endocrine

Question 5

How does the endocrine system work?

Answer 5

Hormones travel via bloodstream to target cells; neurohormones are released via synapses and travel via bloodstream

Question 6

How does the paracrine system work?

Answer 6

Paracrine hormones act on adjacent cells through cell junctions

Question 7

How does the autocrine system work?

Answer 7

Autocrine hormones are released and act on the cell that secreted them

Question 8

How does the intracrine system work?

Answer 8

Intracrine hormones are released and act within the cell that produces them

Question 9

What was Arnold Berthold’s contribution to physiology?

Answer 9

Ablation and replacement
(rooster experiments w/ removing the comb - the comb contributes to testosterone production)

Question 10

What did Claude Bernard contribute to physiology?

Answer 10

Internal milieu
Internal secretions were liberated by one part of the body and traveled via bloodstream to distant target cells.

Question 11

What was Walter cannon’s contribution to physiology?

Answer 11

Coined term homeostasis
Described the ability of the body to regulate its internal environment

Question 12

What were Cannon’s postulates?

Answer 12

1. The nervous system can sense and control internal states (feedback loops)
2. Tonic levels of activity can be varied to change values (tonicity)
3. Antagonistic controls work to opposite ends (neurons)
4. Signals can have different effects in different tissues (specificity)

Question 13

What is the difference between negative and positive feedback loops?

Answer 13

Positive feedback loops amplify the initiating stimulus, moving the system away from its equilibrium whereas negative feedback loops counteract the changes of a system to maintain them in a set point.

Question 14

How does the endocrine system maintain homeostasis?

Answer 14

Secretion of hormones is evoked by a change in the milieu and the resulting action on the target cell restored the milieu to normal

Question 15

How do endocrine glands work w/ “sensing and signaling”?

Answer 15

Endocrine glands regulate the duration and magnitude of hormone release via feedback from target cells

Question 16

What is the difference between the endocrine and nervous systems?

Answer 16

The endocrine system is anatomically discontinuous

Question 17

How/what cell does the endocrine system act on?

Answer 17

A cell is targeted by having a specific receptor for the hormone b/c hormones circulate in blood & will come into contact with essentially all cells

Question 18

What is episodic secretion of hormones?

Answer 18

Hormones may secrete in secretory episodes occurring with different periodicity; pulses can be as frequent as every 5-10 minutes

Question 19

What is the physiological importance of pulsatile hormone release?

Answer 19

Hormones are released at specific intervals to maintain normal bodily functions