Chapter 17

endocrine system

- various glands + glandular cells

- hormones (chemical signals)

- some organs release hormones (ex: kidneys)

endocrine system functions

- internal communication

- control of:

- growth + development

- homeostasis

- metabolism

- response to environment

I can: grow, heal, + mature, responsibly

endocrine is very _ compared to the nervous system

slow

endocrine system targets organs _ instead of being _ like the nervous system

generally - precise/specific

endocrine system sends signals via _, unlike _ like the NS

hormones - NTs

some NTs can be _, like _ + _

hormones - epinephrine + vasopressin (ADH)

the nervous system and endocrine system are _ systems

complementary

TRH

thyrotropin-releasing hormone

TRH function

stimulates release of TSH (thyroid-stimulating hormone) + and PRL (prolactin)

CRH

corticotropin-releasing hormone

CRH function

stimulates ACTH (adrenocorticotropic hormone) secretion

GnRH

Gonadotropin-releasing hormone

GnRH function

stimulates release of FSH (follicle-stimulating hormone) and LH (luteinizing hormone)

GHRH

growth hormone releasing hormone

GHRH function

stimulates release of GH (growth hormone)

PIH

prolactin inhibiting hormone

PIH function

inhibits release of PRL (prolactin)

somatostatin function

inhibits secretion of GH and TSH

types of signaling

- cell-to-cell

- tissue-to-tissue

- synaptic

- paracrine

- autocrine

- endocrine

synaptic signaling can be _ or _

chemical - electrical

chemical synaptic signaling occurs via _

NTs (ex: neuromuscular junction)

electrical synaptic signaling occurs via _

gap junctions (ex: between intercalated discs + cardiomyocytes)

paracrine + autocrine chemical signal types

- small molecules (ex: histamine)

- proteins

paracrine + autocrine has _ on target cells

receptors

paracrine + autocrine local signaling type

short-distance diffusion

- longer than synaptic

paracrine targets _ cells

neighbor

autocrine targets _

itself

both autocrine + paracrine signaling can happen...

at the same time

ex: wound healing

endocrine chemical signal type

hormones:

- small molecules

- proteins

endocrine signaling is _ and carried by...

long-distance - blood or other fluids

target cells must have...

specific receptors

target cells respond by...

- change in metabolism

- change in gene expression

- some action (contraction, childbirth, etc)

target cells usually have _ cell types per _

multiple - hormone

insulin targets _, _, and _

- liver

- skeletal muscle

- adipose tissue

the liver, skeletal muscle, and adipose tissue all have _

insulin receptors

normal blood glucose level

70-110 mg/dL

exocrine glands

- don't signal

- product is secreted (into duct or onto surface)

- mammary glands

- sweat glands

- goblet cells

endocrine cells are closely associated with _

blood vessels

endocrine glands perform _ or _ into ECF

exocytosis - carrier-mediated transport

endocrine glands diffuses from _ into _

ECF - blood

glucose homeostasis antagonist hormones

- insulin

- glucagon

(from pancreas)

glycogenesis

Conversion of glucose to glycogen for storage.

gluconeogenesis

production of new glucose from AAs

glycogenolysis

breakdown of glycogen to glucose

insulin effects the _, _, and _

liver, adipose, skeletal muscle

insulin effects on the liver

- increase glucose uptake from the blood

- increased glycogenesis

- fatty acid synthesis (after glycogenesis)

liver stores glucose as _

fat

series of events in the liver starting at glucose:

glucose -> fatty acids -> to blood -> adipose -> triglycerides

effects of insulin on adipose tissue

- increased glucose uptake from blood

- glucose -> triglycerides

effects of insulin on skeletal muscle

- increased glucose uptake from the blood

- glucose -> glycogen

glucagon effects the _ and _

liver - adipose tissue

glucagon effects on the liver

- glycogenolysis

- gluconeogenesis

glucagon effects on adipose tissue

- increased triglycerides breakdown

- fatty acids -> blood (used for energy to prevent BG from dropping)

the hypothalamus + pituitary gland are located in the _ and connected by the _

diencephalon - infundibulum (pituitary stalk)

pituitary = the _

hypophysis

pituitary lobes

- anterior pituitary

- anterior lobe

- adenohypophysis

- posterior pituitary

- posterior lobe

- neurohypophysis

neuroendocrine cells have properties of both _ and _

neurons and endocrine cells

- ex: hypothalamus

posterior pituitary functions

- hypothalamic projections

- neuroendocrine cells (aka neurosecretory cells)

- stores + releases hormones

hormones are stored in the posterior pituitary as...

vesicles collected in axon terminal branches

- in Herring bodies

the anterior pituitary is controlled by...

neuroendocrine cells in the hypothalamus

hypothalamic hormones ->

anterior pituitary hormones

hypophyseal portal system

a blood vessel system that directly connects the hypothalamus with the anterior pituitary

blood flows from the _ to the _ via the _

hypothalamus - anterior pituitary gland - hypophyseal portal system

the hypophyseal portal system has 2 _

capillary beds

HPA (hypothalamo-pituitary axis)

signaling from H to Anterior P

the HPA can also be extended, for example

hypothalamo-pituitary-adrenal axis

why does the HPA exist?

- complex control

- multiple inputs (both internal + environmental)

- temporal control

hypothalamus controls the _, which controls the _, which controls _

anterior pituitary -> other glands -> target cells

the hypothalamus produces "_" + "_" hormones that target the _

- exception in naming: _

releasing + inhibiting - anterior pituitary - somatostatin

after the hormones arrive at the AP, there are _ effects, but often stimulate _

various - downstream hormones

FSH (follicle-stimulating hormone) targets

ovaries + testes

FSH (follicle-stimulating hormone) effect on females

growth of ovarian follicles + secretion of estrogen

FSH (follicle-stimulating hormone) effect on males

sperm production

LH (luteinizing hormone) targets

ovaries + testes

LH (luteinizing hormone) effects on females

ovulation, maintenance of corpus luteum

LH (luteinizing hormone) effect on males

testosterone secretion

TSH (thyroid-stimulating hormone) targets

thyroid gland

TSH (thyroid-stimulating hormone) effects

growth of thyroid, secretion of thyroid hormone

ACTH

adrenocorticotropic hormone

ACTH (adrenocorticotropic hormone) targets

adrenal cortex

ACTH (adrenocorticotropic hormone) effects

growth of adrenal cortex, secretion of glucocorticoids

PRL (prolactin) targets

mammary glands

PRL (prolactin) effect

milk synthesis

GH (growth hormone) targets

liver, bone, cartilage, muscle, + fat

GH (growth hormone) effects

widespread tissue growth, especially in the stated tissues

ADH

antidiuretic hormone

ADH (antidiuretic hormone) targets

kidneys

ADH (antidiuretic hormone) effect

water retention from urine

OT (oxytocin) targets

uterus, mammary glands

OT (oxytocin) effects

- labor contractions

- milk release; possibly involved in ejaculation

- sperm transport

- sexual affection

- mother-infant bonding

all hormones are secreted by the anterior pituitary, except for _ + _, which are secreted by the posterior pituitary

ADH + OT

feedback inhibition

when the product inhibits its own production

osmolarity

total concentration of ALL dissolved solutes

osmoreceptors

neurons that monitor blood osmolarity (in hypothalamus)

if there's a high osmolarity in kidneys ->

keep water

low BP ->

keep water

in OT release during breastfeeding, _ cells _ to eject product

- also stimulates _ through _

myoepithelial cells (in exocrine glands) - contract

PRL - HPA

thyroid gland hormones

- triiodothyronine (T3)

- thyroxine (T4)

- calcitonin

which thyroid hormones regulate metabolism

T3 + T4

which thyroid hormone regulates blood Ca++

calcitonin