Anatomy 3 Endrocrine System Quiz

Front 1

Describe the endocrine system.

Back 1

Influences metabolic activity by means of HORMONES, chemical messengers that bind to cellular receptors that typically reponses after a lag or seconds or days and must more prolongued than the nervous system

Front 2

What are the major processes of the endocrine system?

Back 2

1 growth and development
2 mobilization of body defenses
3 maintaince of electrolyte water and nutrient balance of the blood
4 regulation of cellular metabolism and energy balance

Front 3

What is endocrinology?

Back 3

the study of the endocrine organs and hormones

Front 4

What are the main difference between exocrine glands and endocrine glands?

Back 4

Exocrine glands produce nonhormanal substances and are ductless
Endocrine glands are DUCTLESS and produce hormones, are rich vascular and lymphatic drainage tissue that recieve their hormones

Front 5

How are the hormone-producing cells in the endocrine system arranged?

Back 5

in cords and branching networks which maximizes contact between them and the capillaries surrounding them

Front 6

Why is the hypothalamus considered a neuroendocrine organ?

Back 6

it produces and releases hormones (along with its neural functions)

Front 7

Which organs contain endocrine tissue and produce hormones as well as exocrine products?

Back 7

Pancreas and Gonads

Front 8

Besides the major endocrine organs which other tissues and organs produce hormones?

Back 8

- Adipose Cells release leptin
- Walls of Sm Intestines, Stomach, kidney and heart

Front 9

Are autocrines and paracrines part of the endocrine system?

Back 9

NO, because they act locally

Front 10

What are hormones?

Back 10

they are chemical substances that are secreted by cells into the exracellular fluids, that regulates the metabolic funciton of other cells in the body

Front 11

How are most of the hormones classified?

Back 11

they can be classified chemically as either amino acid based or as steroids (lipid based)

Front 12

A given hormone that influences the activity of only certain tissue cells is referred to as what?

Back 12

Target Cells

Front 13

How do hormones effect target cells?

Back 13

hormones alter cell activity, they increase or decrease the rates of normal cellular processes (depending on the target cell type)

Front 14

What are the typical changes that hormones produce?

Back 14

1- Opens or Closes ion channels(in order to alter plasma membrane permeability or membrane potential, or both)
2- Stimulates synthesis of proteins or regulatory molecules (such as enzymes within the cell)
3- Activates or deactivates enzymes
4- Induces secretory activity
5- stimulates mitosis

Front 15

What are the two main mechanisms that account for how a hormone communicates with its target cell?

Back 15

depending on: chemical nature of the hormones and the cellular location of the receptor
1- WATER-SOLUBLE HORMONES(all amino acid-based except Thyroid) act on receptors in the plasma membrane coupled with the mediated response of the G proteins

2- LIPID-SOLUBLE HORMONES (steroid and thyroid) act on intercellular receptors, directly activating genes (they are inside because they can enter the cell!)

Front 16

Explain Second-Messenger Systems

Back 16

All amino acid based hormones (except Thyroid) exert their signaling effects through intracellular second messengers, generated when a hormone binds to a receptor on the plasma membrane

-for example, cyclic AMP, which is used by neurotranmitters and olfactory and gustatory receptors

Front 17

What is the main advantage to the second-messenger system?

Back 17

SIGNAL AMPLIFICATION! one hormone can cause several GTP

Front 18

What are the factors that effect the reaction of cAMP?

Back 18

1- type of target cell

2- the specific protein kinases it contains

3- the substrate within that cell available for phosphorylation by the protein kinase

Front 19

T or F, some G proteins inhibit rather than activate adenylate cyclase, thereby reducing the cytoplasmic concentration of cAMP, so even slight changes in the level of antagonistic hormones can influence a target cells's activity

Back 19

TRUE

Front 20

Being lipid soluble, where do steroid hormones (and thyroid hormones)bind to their target cells?

Back 20

-they bind to an intercellular receptor that is activated by the coupling

-this activated hormone-receptor complex them makes its way to the nuclear chromatin, where the hormone receptor binds to a region of DNA specific for it

-this interaction "turns on" a gene to produce messenger mRNA

-the mRNA is then translated on the cytoplasmic ribosomes, producing specific protein molecules

-this promotes the synthesis of either structural proteins or proteins to be exported from the target cell

Front 21

What happens to the intracellular receptors, in the absence and presence of hormones?

Back 21

- the receptors are bound up in receptor-chaperonin complexes, associations that seem to keep the receptos from binding to DNA and perhaps protect them from proteolysis

-when the hormone is present, the complex dissociates, which allows it to bind to DNA and influence transcription

Front 22

T or F, Hormones are molecular triggers rather than informational molecules?

Back 22

True

Front 23

What are the three factors for target cell activation by hormone-receptor interaction?

Back 23

1- blood levels of the hormone
2- numbers of receptors (in or on the target cells)
3- affinity(strength) of bond between the hormone and the receptor

*note: all three factor change rapidly in response to various stimuli and changes within the body

Front 24

What is up-regulation?

Back 24

when target cells form more receptors in the response to rising blood levels of the specific hormones to which they respond

Front 25

Can prolonged exposure to high hormones concentrations desensitize the target cells, so they respond less vigorously to hormonal stimulation?

Back 25

Yes! depends on receptor and cell types

also called down-regulation

Front 26

How does down-regulation work?

Back 26

it involoves loss of receptors and prevents the target cells from overreacting to persistently high hormone levels

Front 27

Can hormones effect the number and affinity of not only their own receptors, but also the receptors of other hormones?

Back 27

Yes!

-progesterone=loss of estrogen receptors in the uterus
-estrogen then causes the same cells to produce more progesterone receptors (older sister hits you, you hug her more!)

Front 28

What are the two forms that hormones circulate in the blood?

Back 28

FREE or BOUND TO A PROTEIN CARRIER

-generall, steroids and thyroid (lipid-soluble) travel in the bloodstream attached to plasma proteins

-most other circulate inencumbered by carriers

Front 29

What does the concentration of hormone in the blood at any time reflect?

Back 29

1- its rate of release

2- the speed at ehich it is inactivated and removed from the body

Front 30

How are most hormones removed from the body?

Back 30

- some are rapidly degraded by enzymes in their target cells

- most are removed by the kidneys or liver (and their breakdown prodects are excreted by urine and some in feces)

-half life varies from a fraction of a minutes to a week (water-soluble having the shortest half life)

Front 31

T or F, steroid hormones require hours to days before their effects are seen?

Back 31

True

Front 32

T of F, some hormones are secreted in a relatively inactive form and must be activated in the target cells?

Back 32

True

Front 33

Describe the time required for hormone effects to appear and the duration of the action of the hormone

Back 33

Time required varies, some immediate and other hour to days (esp steroids)

Duration action is limited ranging from 10 seconds to several hours

Effects may dispear rapidly as blood levels drop, or may persist for hours after very low hormones levels have been reached

Front 34

What are the three major types of stimuli that are used in endocrine glands to relase their hormones?

Back 34

humoral
neural
hormonal

Front 35

Describe Humoral Stimuli.

Back 35

-bloodborne
-simplest of endocrine control systems
-secrets hormones in direct response to changing blood levels of certain critical ions and nutrients
-examples are parathyroid (PTH in response to Ca++), pancreas (insulin), and adrenal cortex (aldosterone)

Front 36

Describe Neural Stimuli.

Back 36

-in a few cases, nerv fibers stimulate hormone release

-sympathetic NS stimulation of adrenal medulla to release catecholamines (NE and Epinephrine) during stress

Front 37

Describe Hormonal Stimuli.

Back 37

-when endocrine gland release their hormones in responce to hormones produced by other endocrine organs

-ex: RELEASE OF MOST ANTERIOR PITUITARY HORMONES IS REGULATED BY RELEASING AND INHIBITING HORMONES PRODUCED BY THE HYPOTHALAMUS, AND MANY ANTERIOR PITUITARY HORMONES IN TURN STIMULATE OTHER ENDROCRINE ORGANS TO RELEASE THEIR HORMONES