Gen bio 2 exam 2 real

Water soluble hormones (polypeptides always)

exits cell via exocytosis
dissolves in blood stream
interacts with cell via signal transduction - gpcr

is water soluable pathway fast or slow response

fast because acting on proteins already existing, lasts short time

Lipid soluble pathway

diffuses through membrane
travels in bloodstream via lipid carrier proteins
then diffuses through cell membrane and gets into nucleas with a bound receptor that changes gene expression

slow response , longer duration

Hypothalamus 2 modes of action

acts on AP (sends IH or RH via portal vessels - vascular)
acts on PP ( makes hormones wich are sent to PP through axons) then stored in vesicles until needed

3 types of AP hormones

Tropic - interdmediate singal, acts on another endocrine gland

non tropic - acts directly on muscle/tissue, direct physiological effect
both

Thyroid functions

Stimulate cellular metabolism in virtually all cells

Maintain normal BP, heart rate, muscle tone

Regulate digestive, reproductive functions

general thyroid hormone pathway

TRH - TSH -TH

Hypothalamus secretes thyrotropin-releasing hormone (TRH)

Stimulates AP to secrete thyroid-stimulating hormone (TSH)

Stimulates thyroid gland to secrete thyroid hormone (TH)

TH is regulated by what mechanism

negative feedback.

hypothyroidism

Not enough TH in body, excess TSH from AP causes thyroid glands to become large, never ending cycle until iodine deffincy is fixed and thyroid can make TH again.

hyperthyroidism

In Grave's disease, antibodies mimic TSH by binding to thyroid receptors, causing permanent activation that overrides negative feedback and leads to excessive TH secretion

Adrenal glands

Sit on top of kidney’s and have two parts, adrenal medulla and adrenal cortex

Adrenal Medulla

acute stress, nerve impulses sent from, hypothalamus, and primarily rleases epi and norepi.


effects: more blood to brain, muscles, heart

glycogen broken down to glucose

increase metabolic rate (up to 100%)

increase O2 delivery

Adrenal Cortex

Deals with chronic stress and endocrine system.

Stress → hypothalamus secretes corticotropin-releasing factor (CRF)

→ AP releases adrenocorticotropic hormone (ACTH)

→ ACTH stimulates adrenal cortex to produce corticosteroids

2 types of corticosteroids

Glucocorticoids- produces glucose from non carb sources (muscle breakdown). supresses immune system at high levels.

Mineralocorticoids - maintains ion homeostasis, salt and water balance. excess can cause hypertension by causing kidneys to retain salt, therefore making blood saltier. water follows salt, and increases volume inside blood vessels in arteries.

primitive response to dehydration/hypovolemia.

seminiferous tubes

site of spermatogenesis, coilied within testes.

leydig cells

surround seminiferous tubes, make test

epididymus

transports sperm
matures sperm
stores sperm

seminal vesicle

Produce fluid that contains: Fructose – energy for sperm after ejaculation and Prostaglandins – stimulate contractions of uterus

secreted into vas deferens, accounts for 60% of semen volume and is forensically significant

prostate gland

secretes fluid with anticoag enzymes and citrate into eurethra during ejactulation

Bulbourethral gland

pre cum, 1st gland to secrete during arousal, Contain mucus to neutralize acidic urine

sperm path

Sperm are produced in the seminiferous tubules of the testes, mature in the epididymis, travel through the vas deferens, enter the ejaculatory duct to mix with seminal and prostatic fluids, and finally exit the body via the urethra.

spermatogenesis

primordial germ cells differentiating into spermatogonial stem cells, which divide via mitosis into spermatogonia; who specialize into primary spermatocytes (2n) that undergo meiosis I to become secondary spermatocytes, followed by meiosis II to produce spermatids, which finally mature into sperm cells.

Male endocrin

hypothalamus releases GnRH → AP releases two gonadotropins (LH) (FSH)

LH: targets Leydig cells in testes to produce testosterone

FSH: dev of seminiferous tubes & stimulates sertoli cells to make ABP and inhibin (stops FSH secretion)

Ovaries

female sex organ, production and release of mature eggs

oviducts (fallopian tubes)

Collect secondary oocytes from ovary, move to uterus, Move via beating cilia, contractions

Site of fertilization

uterus

site of emrybonic dev, has two layers: myometrium thick wall of smoth muscle, endometrium - Connective tissue, glands, blood vessels

Thickens each moth – prepare for pregnancy

Fertilization – embryo implants into endometrium

No fertilization – sloughed off – menstruation

cervix

closes uterus and separates it from vagina

oogenesis (embryonic stage)

2n primoridal germ cells divide to become oogonia 2n who develop to become primary oocytes who start meiosis but arrest in prophase 1.

oogenesis post embryonic stage

6–12 follicles begin maturing in the ovary each month, but only the largest allows its primary oocyte ($2n$) to complete meiosis I. This division uses unequal cytokinesis to produce a small first polar body ($n$) and a large secondary oocyte ($n$), which then starts meiosis II but arrests at metaphase II. During ovulation, this arrested oocyte is ejected into the oviduct, where it will only complete meiosis II to become a mature ovum if it is successfully penetrated by a sperm.