Ch. 6 Respiratory System part 8

pituitary gland is a

composite gland because it develops partly from the roof of the mouth via a structure called Rathke's pouch.

The anterior pituitary (adenohypophysis) is

non-nervous tissue and is divided into the pars distalis and pars intermedia

e pars distalis, which secretes

growth hormone, prolactin, FSH, LH, TSH, and ACTH,

pars intermedia, which produces

melanocyte-stimulating hormone (MSH)

hypothalamus makes

ADH and oxytocin

-makes nerous component

ADH and oxytocin are part of hypothalamis

nervous component

The posterior pituitary

-(neurohypophysis)

a neural extension of the hypothalamus and is made up of the pars nervosa.

The posterior pituitary acts as a

as a neurohemal organ, meaning it releases ADH and OT directly into the bloodstream

sella turcica is a

saddle-shaped depression in the sphenoid bone where the pituitary gland sits

hormones from anterior piutuitary are

mostly prtiens

The gonadotropins are

e FSH and LH

The gonadotropins can on

on the gonads to mkae gametes

TSH, or thyrotropin,

controls the thyroid gland

ACTH, or corticotropin, acts on the

adrenal cortex

MSH, melanocortin, influences

skin pigmentation.

GH STANDS FOR

somatotrpoin

GH acts on

s on body tissues—like bone, cartilage, and muscle—promoting growth

thyrotropin-releasing hormone (TRH) mechnaism

-made in hypothalamus

- travels to the pituitary,

-prompting the release of TSH (thyrotropin).

-TSH then acts on the thyroid gland to stimulate production of T3 and T4.

corticotropin-releasing hormone (CRH) mechanism

-made in hypothalamis

-which signals the pituitary to release ACTH (corticotropin).

-ACTH then targets the adrenal cortex to produce cortisol.

GnRH-gonadotrophin release hormone mechanism

-made in hypothalamus

-goes to pituitaty

-makes gondatropis FSH and LH

FSH in females stimulates

follicular maturation and stimulates estradiol 17Bproduction

FSH in males

spermatogensis

LH in females stimulates

ovulation

LH in males stimulate

testosterone

GHRH (growth hormone-releasing hormone) mechanism

-make in hypothalmis

-goes to pituitary

-releases grwoth hormones

SRIF (somatostatin) inhibits

growth hormone release

PIF

, stops prolactin release from the pituitary

PIF is

prolactin inhibiting factor

-aka dopamine

inhibiting hormones are

SRIF (somatostatin)

PIF (dopamine)

Negative feedback hormones

TRH (thyrotropin-releasing hormone)

CRH (corticotropin-releasing hormone)

Hormones of posterior pituitary

oxytocin and ADH

Oxytocin example

-contraction of smooth muscles of uterus at parturition

-milk let down

Anti Diuretic hormone example

water reabsorption in kidneys via aquaporins water channels

Tallest man ever

Robert Wadlow was the tallest man ever

-8.11 inches

acromegaly

-high growth hormones in adult

-in the tallest man

gigantism

to excess of growth hormones in youth

largest endrocrine gland

Thyroid gland

thyroid gland location and what is has

-In front of larynx

-Rich in blood supply

-Made of follicles with cuboidal cells

thyroid gland # of follicles and lobes

-Has 3 million follies

-2 lobes

-a central isthmus

Inside thyroid gland follicles are

protein-rich substance called colloid

what does colloids has

thyroglobulin

Between the follicles

you've got parafollicular cells (or C cells)

what do c cells do

produce calcitonin.

thyroid gland follciles have which cells

lined by cuboidal cells called thyrocytes

Determination of T3/T4 is based on

-iodine amount

-where it attaches to tyr

if one tyrosine gets one iodine, you get a

mono-iodotyrosine (MIT

1 tyr with two iodines is

diiodotyrosine (DIT).

When you combine one MIT and one DIT, you get

T3

When you combine two DITs, you get

t4

Iodide trapping

process by which I- is transported into thyroid cell from blood

How does I- enter thyroid cell

at the basolateral membrane, along with sodium (Na+), via the sodium-iodide symporter (NIS)

Once I- enter thyroid cell what occurs

sodium is pumped out and potassium (K+) is brought in by the Na+/K+ ATPase pump.

From basolateral where does I- go

to apical side where I- is oxidized then hooked with tyr on thyroglobulin

iodinated thyroglobulin goes where

stays stored in the follicle. hen, when needed, the thyroglobulin is taken back into the thyrocyte in lysosomes, where it's broken down, releasing T3 and T4

monoiodotyrosin

MIT

diiodotyrosine

DIT

MIT and DIT are

recycled and dont exit

Tetra-iodo thyronine

T4

Tri-iodo thyronine

T3

Role of T3/T4

controls BMR

adult BMR is

39kcal/hour/m2 body surface-adult 2m^2

BMR is higher is

active individial

BMR vs size

BMR is higher in smaller like mic than elephant

BMR links to

How much o2 is needed to burn and make ATP

high BMR= more O2 needed

T3/T4 is also important for

Physical, mental and gonadal growth

Low T3/T4 in childhood leads to

cretinism

Thyroid regulation occurs thru

negative feedback

-T3/T4 act to suppress TSH

-high T3/T4= low TSH normally

abnormal conditions in thyroid gland does what

body can produce antibodies—immunoglobulins (Ig)—that mimic TSH.

These antibodies overstimulate the thyroid, causing it to make too much T3 and T4

Too much T3/T4 means

hyperthyrodism

Graves disease can lead to

hyperthroidism

-autoimmune condition where those antibodies keep the thyroid in overdrive