14. endocrine system

Question 1

nervous sys vs endocrine sys

Answer 1

nervous:
fast, delivers to individual cells, effects resolve quickly, faster AP

endocrine:
slower, longer lasting effects, widespread, longer AP

Question 2

describe 4 charcteristics of a hormone

Answer 2

1. produced and released by an endocrine or neuroendocrine cell
2. exert regulatory influence on the function of distant cells
3. be effective at very low concentrations (nanomolar (10-9) - picomolar 10-12range)
4. be carried via the bloodstream to its target cells

Question 3

the processes that the endocrine system control is?

Answer 3

• produced and released by an endocrine or neuroendocrine cell
• exert regulatory influence on the function of distant cells
• be effective at very low concentrations (nanomolar (10-9) - picomolar 10-12range)
• be carried via the bloodstream to its target cells

Question 4

paracrine

Answer 4

signal nearby (neighbor) cells

Question 5

autocrine

Answer 5

signal the same cell that they belong to

Question 6

why are autocrine and paracrine not considered hormones?

Answer 6

they do not enter the bloodstream

Question 7

why is carbon dioxide not considered a hormone?

Answer 7

although this gas is carried through the bloodstream, it is not produced by endocrine cells

Question 8

haemocoel

Answer 8

The cavity, between the organs of arthropods and molluscs, through which the blood etc. circulates.

open circulatory sys

Question 9

Endocrine chemical signals diffuse from their cell of production into

Answer 9

capillaries (closed circulatory systems)

haemocoel (open circulatory systems)

Question 10

Further delay in endocrine response can occur because some hormones

Answer 10

• –are produced only upon stimulation of the cells that make them.
• –Time required for synthesis delays hormonal effect.
• –are transcription factors.
• –Time required for translation delays hormonal effect.

Question 11

hydrophobic hormones example

Answer 11

they are lipid soluble and are bound hormones bc they need plasma transporters in blood like albumin to help them

ex: steroid and thyroid

Question 12

hydrophilic hormone example

Answer 12

free hormones bc they can go directly in plasma blood which is mostly water

ex: monoamine and peptide

Question 13

free fraction

Answer 13

percentage of hormone that is unbound (free) at any given time

Question 14

3 benefits of blood transport proteins:

Answer 14

— help protect hormones from being broken down by enzymes

— prevent kidneys from filter hormones

— prolong half time of hormones they are transporting so that it can stay in blood for hours days or weeks

Question 15

Endocrine cells are commonly divided into two major classes:

Answer 15

epithelial (nonneural) cells

neurosecretory cells

Question 16

Epithelial cells

Answer 16

may be dispersed in epithelia
may comprise discrete epithelial glands.
typically are activated by hormones from other sources
may also receive neural input
example: β cells of the pancreas

Question 17

Neurosecretory Cells

Answer 17

–synthesize neurohormones in their cell bodies
–release neurohormones into the bloodstream, not the synaptic cleft
are signaled to secrete neurohormones by typical neurons
–convert neural signals into chemical (neurohormone) signals.
have cell bodies in the CNS, axons outside the CNS
–may communicate directly with nearby target cells OR
–may form a neurohemal organ

Question 18

neurohemal organ

Answer 18

• -is a cluster of highly vascularized neurosecretory axon terminals
• -transports neurohormones to distant cells

Question 19

gland

Answer 19

one or more cells that produce and secrete a particular product

Question 20

define exocrine

Answer 20

(product is secreted onto skin or into body cavities)

Question 21

give 6 ex of an exocrine gland secretion

Answer 21

milk 
oil 
sweat 
bile 
mucus 
digestive enzymes

Question 22

exocrine vs endocrine

Answer 22

although both are involved in secretions, endocrine secretes into body tissues directly through the blood stream

exocrine secretes through ducts onto the body or surface of body cavities BUT NEVER EXACTLY INSIDE

Question 23

define endocrine

Answer 23

(product (hormone) is secreted inside the body)

Question 24

name 5 types of endocrine cells

Answer 24

unicellular
multicellular
discrete 
diffuse
intermediate

Question 25

discrete

Answer 25

endocrine cells grouped and adhered together (e.g., thyroid)

Question 26

diffuse

Answer 26

scattered among non-endocrine cells (e.g., intestinal epithelium)

Question 27

intermediate

Answer 27

between discrete and diffuse (e.g., Islets of Langerhans)

Question 28

give 8 examples of endocrine gland

Answer 28

pituitary 
pineal 
pancreas 
gonads (ovaries, testes) 
thyroid gland 
parathyroid 
hypothalamus 
adrenal

Question 29

where is the pituitary gland located?

Answer 29

pea-sized gland housed
within a saddle-shaped extension of the skull’s sphenoid bone,
(((((the sella turcica (Latin: “Turkish saddle”) at the base of the brain))))

Question 30

why is the pituitary gland also called the master gland?

Answer 30

The pituitary controls the function of most other endocrine glands.

Question 31

roles of the hypothalamus

Answer 31

–links the afferent nervous system
to the endocrine system via the pituitary gland.

controlling
body temperature 
thirst 
hunger 
other homeostatic systems 
reproductive cycles 
sleep

Question 32

amino acid vs lipid derivative hormones

Answer 32

amino acid-based (water soluble) - enter cells via membrane channels

lipid derivatives (fat soluble) - enter cells through the plasma membrane

Question 33

steroid hormones

Answer 33

are synthesized from cholesterol (a lipid coming from animal fat or we synthesize ourselves)
are lipid-soluble

can enter cell through plasma membrane or be endocytotically transported

act on receptor molecules inside their target cells

Question 34

examples of steroid hormones

Answer 34

hormones of the gonads and adrenal cortex
hormones produced in skin
placental hormones
insect molting hormones