BIOL 191B Exam 3

(Reproductive, Endocrine, Sensory)

Scrotum

• sac of loose skin encasing the testes; regulate the temperature of the testes

  • Adjust how close testes are to the body

  • Cold scrotum shriveled and tight to body to stay warm but colder than rest of body system

Testes

paired, oval glands in the scrotum partially covered by the tunica vaginalis

Seminiferous tubules

• carry sperm produced within them (spermatogenesis) out of the testes

  • Into network called rete testis (testicular network)

  • Sperm goes into epididymis (bundle of ducts)

  • Allows sperm to be produced

epididymis

• Sperm mature in this structure and degenerate sperm are reabsorbed

  • propels sperm into the ductus deferens, allowing them to move

ductus deferens

• transport sperm from the epididymis to the urethra during ejaculation

• exits the epididymis and ascends through the spermatic cord then it loops over the ureter and down the posterior surface of the bladder

Spermatic cord

• is a collection of ducts, vessels, and nerves

• Function to provide blood to testes, regulate testicular temperature and guide sperm out of the testes

  • Produce nutrients

  • Guiding sperm out of testes through ductus deferens

Seminal vesicles

• secrete an alkaline, viscous fluid containing fructose, prostaglandins and proteins

  • Give sugar and protein to sperm (nutrients)

  • Prostaglandins- immune system molecules that neutralize response from female system

Prostate

• a gland that secretes a milky, slightly acidic fluid containing citric acid, enzymes and acid phosphatase.

  • More thin fluid, enzyme and acid helps with fluidity of fluid (helps sperm travel)

Bulbourethral glands

• secrete an alkaline fluid during sexual arousal that neutralizes acids from urine

  • During sexual arousal and intercourse

  • Don't want to kill of own sperm from acidity of urine

  • Gland secreted to neutralize acidity in urethra to lubricate and so sperm don’t die

Semen

a mixture of sperm and seminal fluid

Penis

• contains the urethra; passageway for semen & urine

  • corpora cavernosa leads to size and girth

  • Corpus spongiosum holds a lot of fluid; holds it in container and harden

  • Leads to erection

  • Glans: Head of penis covered by the prepuce

GnRH

• from hypothalamus works with cells (gonadotroph)  in pituitary gland

• Produces LH and FSH

LH (male)

• stimulates cells in the testes to produce testosterone

  • Activating interstitial cells that produce testosterone

  • Turns into DHT (sex hormones in males)

  • Naturally becomes DHT from testosterone

FSH (male)

• stimulates and leads to spermatogenesis

  • Stimulates production of sex cells (sperm/ egg)

Inhibin (male)

•  (inhibits) decreases FSH release

  • Important for regulating sperm cells

  • Not too many or too few

  • Secreted by same cells that produce sperm

Testosterone

• Overall muscle mass & fat distribution

  • Puberty tend to gain muscle mass

  • Distribute fat differently/ grow out of chubbiness

• Motivation, mood, confidence

  • Low T tend to be unmotivated

  • unconfident

• Sex drive and erectile function

DHT

• Important for development of male sex organs

  • Facial hair and body hair growth

    • contributes to more body and facial hair

    • A lot of receptors on scalp contributes to male pattern baldness

  • Prostate development and growth

  • Contributes to deepening of the voice

Ovaries

• paired glands homologous to the testes

• produce gametes (egg cell [ovum]) and hormones (progesterone, estrogens, inhibin, relaxin)

Germinal epithelium

covers the surface of ovary

Tunica albuginea

• capsule of dense irregular connective tissue below the germinal epithelium

Ovarian cortex

• below the tunica albuginea and consists of ovarian follicles and stromal cells

Ovarian medulla

• contains connective tissue, blood vessels, lymphatic vessels and nerves

Ovarian follicles

• contain oocytes in various stages of development, follicular cells, and granulosa cells

• Provides structure and support for egg

corpus luteum

• develops after ovulation when the empty follicle produces progesterone, estrogen, and relaxin

  • Once ovulation occurs/ exits follicle

  • Follicle becomes this strucutre

  • Produce progesterone; important for uterus to be ready for egg cell to be fertilized

uterine (fallopian) tubes

• that extend from the uterus to the ovary

  • The tubes are the pathway for the sperm to reach the ovum and for fertilized ova to travel to the uterus

uterus

• where a fertilized ovum will implant & develop

• If fertilized ovum does not implant, the inner lining of the uterus sheds leading to menstruation

three layers to the uterus:

1. The perimetrium is the outermost layer

2. The myometrium is the middle layer, consisting of three layers of smooth muscle (contractions)

3. The endometrium is the inner layer

• stratum functionalis layer shed in menstruation

• stratum basalis layer is permanent

Cervix

• produces mucus which is more hospitable to sperm during ovulation allowing sperm to get to uterine tubes

  • Water like for sperm to be able to travel

  • Becomes thick after ovulation

• Acts as barrier to prevent pathogens from entering uterus thus protecting developing fetus in uterus

• Dilates and opens up during labor to allow baby to pass

vagina

• a fibromuscular canal lined with mucus that extends from the body’s exterior to the cervix

hymen

• a thin fold of vascularized mucous membrane that partially closes the inferior end of the vagina

  • During intercourse this lining is ripped

  • Causes bleeding referred to as “popping the cherry”

vulva

• refers to the external genitalia of the female

  • This structure includes:

  • Mons pubis – fatty mass on top of pubic bone

  • Labia minora & majora – protect vagina from pathogens

    • Minora similar to inside of mouth; moist, pink more delicate

    • Majora more like the skin; dry and covered in epithelium

Clitoris

• sensitive organ densely packed with nerves

Functions in lubrication, sexual stimulation, and orgasm

Paraurethral glands

• secrete mucus and are embedded in the wall of the urethra

  • They are homologous to the prostate

  • Proper lubrication

Greater vestibular glands

• produce mucus during sexual arousal to provide lubrication

  • They are homologous to the bulbourethral gland

  • The vestibular bulb has two masses of erectile tissue that engorges (erect/ harden) during sexual arousal to narrow the vaginal orifice applying pressure to the penis during intercourse

    • It is homologous to the erectile tissues of the penis

ovarian cycle

• includes changes that occur during and after maturation of the oocyte

  • Three phases (5:27)

  • Follicular phase- maturing follicles (houses eggs)

    • Only mature follicle should mature/ ovulate egg 

    • One dominant follicle (Graafian)

  • Ovulatory phase- single egg cell will ovulate from a single ovary

    • One ovary with single follicle

  • Luteal phase- corpus luteum (yellow body)

    • Egg is house in follicle and when egg ovulates it’s left on its own

    • Then becomes corpus luteum

    • Very functional in secreting hormones

uterine cycle

• involves changes in the endometrium that prepare it for implantation of the developing embryo

• Innermost layer of the uterus

  • Starts with menstruation

    • Happens for a week or less

    • Losing endometrium

    • As cells die tissue shed and bleeding occurs

  • Proliferative phase

    • Tissue is very thin but prepares for ovulation by becoming thicker

  • Secretory phase

    • uterine glands packed with nutrients for fertilized ovum

    • If fertilization and implantation occurs; no menstruation (could be pregnant or late period)

Estrogen

• Promote development and maintenance of female reproductive structures and secondary sex characteristics

• Increase protein anabolism

• Lower blood cholesterol

  • When women go through menopause (lack of follicles to produce estrogen)

• Stimulates proliferation of stratum basalis to form a new stratum functionalis after menstruation occurs

  • Drives cell division and phase

• Moderate levels inhibit release of Gn

Inhibin (female)

• Inhibits FSH

• Regulator of ovulation and spermatogenesis

• Don't want too much production

• Quality over quantity

LH (female)

• Stimulates ovulation

• LH surge; huge amount of LH and ovulation

• Ovulation means egg cells is coming out of ovary and going into fallopian tube

Relaxin

• Inhibits contractions of uterine smooth muscle

• During labor, increases flexibility of pubic symphysis and dilates uterine cervix 

• Not secreted by corpus luteum during labor

Progesterone

• During follicular phase does not produce

• It is the hormone that stimulates the endometrial glands to secrete glycogen and lipids

• Its serves as a nutrient courses for a fertilized egg in implantation occurs

• High levels can inhibit the release of GnRH, LH, and FSH

Fertilization

• merging of genetic information from haploid sperm and haploid secondary oocyte

cleavage

After fertilization (at about 24 hours), the zygote begins mitotic division

blastomeres

• By the end of the third day there are 16 cells

Each division yields smaller and smaller cells

morula

• By the fourth day the cluster of cells resembles a mulberry

• It is still surrounded by the zona pellucida and is still the size of the zygote

blastocyst

• At the 32-cell stage, the fluid now inside the morula rearranges the blastomeres into a large, fluid-filled cavity

• Inside is a cavity with fluid

• Cells migrate outside

embryoblast

 (inner cell mass) will develop into the embryo

trophoblast

(outer cell mass) will develop into outer chorionic sac surrounding the fetus, and the fetal portion of the placenta

chorion

• Blocks antibody production by the mother

  • Tells body to not attack the developing embryo

• Promotes production of T lymphocytes to suppress the immune response in the uterus

• Produces human chorionic gonadotropin (hCG)

  • Maintains the endometrium

  • Looks for this hormone in pregnancy test

  • 12 days after fertilization

placenta

• exchanges nutrients, oxygen and waste products between mother and fetus

  • Requires a lot of energy to develop embryo

  • Leads to more eating or cravings in women

nervous and endocrine systems

•  act together to coordinate all systems of the body

• The nervous system releases neurotransmitters; the endocrine system releases hormones

Molecules

• Nervous: Neurotransmitters released locally in response to nerve impulses.

• Endocrine: Hormones delivered to tissues throughout the body by blood

Site of Action

• Nervous: Close to site of release, at synapse; binds to receptors in postsynaptic membrane

• Endocrine: Far from site of release (usually); binds to receptors on or in target cells

Types of target cells

• Nervous: Muscle (smooth, cardiac, and skeletal) cells, gland cells, other neurons

• Endocrine: Any cells throughout body with

Time to onset of action

• Nervous: Typically within milliseconds (thousandths of a second)

• Endocrine: Seconds to hours or days

Duration of action

• Nervous: Generally briefer (milliseconds)

• Endocrine: Generally longer (seconds to days).

gland

a single cell or a mass of epithelial cells adapted for secretion

endocrine glands

• enter the interstitial fluid then diffuse into the bloodstream

• Secrete hormones around them in capillaries through capillary exchange

exocrine glands

• enter ducts that empty onto the surface of a covering such as the skin surface or the lumen of the stomach

• Not always external to the skin; sometimes through duct and releases through another part of the body (ex. Lumen of stomach)

hypothalamus and pituitary gland

• work together to control other endocrine glands

thyroid gland

• a butterfly-shaped gland located inferior to the larynx and anterior to the trachea

  • It has right and left lateral lobes connected by an isthmus

• Help maintain normal body temperature

• Stimulate protein synthesis

• Increase the use of glucose and fatty acids for ATP production

• Work with hGH and insulin to accelerate body growth

adrenal glands

• covered by a connective tissue capsule

• The glands are divided into two regions:

  • The outer cortex

  • The inner medulla

pineal gland

• attached to the roof of the third ventricle of the brain and secretes melatonin

  • Melatonin helps to regulate the body’s biological clock

thymus

• located behind the sternum between the lungs and produces thymosin, thymic humoral factor (THF), thymic factor (TF), and thymopoietin

  • These hormones promote maturation of the immune system’s T cells

Growth hormones (GH)

• Stimulates liver, muscle, bone and other tissues to release insulin-like growth factors (IGFs)

• Both GH and IGFs work together to promote growth of body tissues

• GH is important to tell cells to release IGF

• GH acts directly on target cells without IGFs to enhance lipolysis (breakdown of lipids) and decrease glucose uptake

Thyroid-stimulating hormone (TSH)

• Stimulates synthesis and secretion of thyroid hormones by thyroid gland

Follicle-stimulating hormone (FSH)

• In females, initiates development of oocytes and induces ovarian secretion of estrogens

• In males, it stimulates testes to produce sperm

• Making more egg cells and sperm cells

Luteinizing hormone (LH)

• In females, it stimulates secretion of estrogens and progesterone, ovulation, and formation of corpus luteum

• In males, stimulates testes to produce testosterone

Prolactin (PRL)

• Together with other hormones, it promotes milk production by mammary glands

• Production and ejection of milk are different hormones

Adrenocorticotropic hormone (ACTH)

• Stimulates secretion of glucocorticoids (mainly cortisol) by adrenal cortex

Melanocyte-stimulating hormone (MSH)

• Produces pigmentation of the skin when activated by UV light

• Epithelial cells producing melanin; stimulate melanocytes

• Triggers production of MSH

• Suppresses appetite and contributes to sexual arousal

Oxytocin

• released in response to stretch placed on the cervix during childbirth.

• affects the:

  • Mother’s uterus – enhances contractions

  • Mother’s breasts – stimulates milk ejection by the mammary glands in response to suckling

  • Love hormone- very high levels create instant bond with baby

T3 (triiodothyronine) and T4 (thyroxine)

thyroid hormones from follicular cells

• Increase metabolic rate (body temp)

• Cells will produce more proteins 

• Use more ATP to produce proteins

• Accelerate body growth and development of nervous system

Calicitonin (CT)

from parafollicular cells

• Lower blood levels of calcium by inhibiting bone reabsorption

• Body essentially eating its own tissue

• Accelerate uptake of calcium and phosphate into bone extracellular matrix

Parathyroid Glands

• Chief cells that produce parathyroid hormone (PTH)

  • Primary functional cells

• PTH is released when calcium levels are low

• It increases Ca2+ reabsorption by kidneys; promotes formation of calcitriol; increases bone resorption

• Oxyphil cells whose function is not known in normal parathyroid glands, but which secrete excess PTH in cases of parathyroid cancer

  • Could be support cell

  • Provides sustenance to chief cells

  • Well vascularized to travel around body

Mineralocorticoids

• from zona glomerulosa

  • Increase blood levels of Na+ and water; decrease blood level of K+.

Glucocorticoids

• from zona fasciculata

  • Upregulate expression of anti-inflammatory proteins; regulates blood glucose levels by stimulating gluconeogenesis and lipolysis

Androgens

• from zona reticularis

  • ACTH stimulates secretion

    • Assist in early growth of axillary and pubic hair in both sexes; in females, contribute to libido and are source of estrogens after menopause

Epinephrine and norepinephrine

• from adrenal medulla

  • Increase heart rate & blood flow to muscles, increase breathing rate; bronchodilation

    • Vasoconstriction to raise blood pressure to get it where it needs to go

Glucagon

• from Alpha Cells

  • Raises blood glucose level by accelerating glycogenolysis and gluconeogenesis.

Insulin

• from Beta cells

  • Lowers blood glucose level by accelerating glycogenesis, increasing lipogenesis and stimulating protein synthesis.

Somatostatin

• from Delta cells

  • Pancreatic polypeptide inhibits secretion

    • Inhibits secretion of insulin and glucagon; slows absorption of nutrients from GI tract (digestion)

Pancreatic polypeptide

• from F cells

  • Inhibits somatostatin secretion, gallbladder contraction, and secretion of pancreatic digestive enzymes (tell pancreas to release juices for digestive enzymes)

Epidermal growth factor (EGF) 

Produced in salivary glands; stimulates proliferation of epithelial cells, neurons, and neuroglia; suppresses cancer cells and secretion of gastric juice by stomach

Platelet-derived growth factor (PDGF)

Produced in blood platelets; stimulates proliferation of neuroglia, smooth muscle fibers, and fibroblasts; appears to have a role in wound healing.

Fibroblast growth factor (FGF) 

• Found in pituitary gland and brain; stimulates proliferation of smooth muscle fibers, chondrocytes, and endothelial cells; stimulates formation of new blood vessels (angiogenesis).

Nerve growth factor (NGF) 

Produced in salivary glands and hippocampus of brain; stimulates growth of ganglia in embryo; maintains sympathetic nervous system; stimulates hypertrophy and differentiation of neurons.

Tumor angiogenesis factors (TAFs)

Produced by tumor cells; stimulate growth of new capillaries, organ regeneration, and wound healing.

Gigantism

• caused by excess secretion of growth hormone

  • Causes overgrowth of hands, face and feet

Goiter

• caused by a reduction or overproduction of thyroid hormone (TH)

Causes difficulty breathing and swallowing

Hypothyroidism

• develops due to insufficient TH

Causes depression, weight gain, cold intolerance

Graves

• disease develops due to excess thyroid hormone

Causes irritability, muscle weakness, heat intolerance

Cushing’s

• syndrome is caused by excess secretion of glucocorticoids

  • Causes abdominal obesity, weak muscles and bones, fragile skin that heals slowly

Stimulation

• is the any event that triggers a specific physiological reaction in an organ or tissue

Transduction

• is the process of converting a sensory signal into an electrical nerve signal processed by the CNS

Sensation

is the conscious or subconscious awareness of changes in the external or internal environment

Perception

•  is the conscious interpretation of sensations performed mainly by the cerebral cortex

Free nerve endings

• Bare dendrites associated with pain, thermal, tickle, itch, and some touch sensations.

Encapsulated nerve endings

Dendrites enclosed in connective tissue capsules for pressure, vibration, and some touch sensations.

Separate cell

• Receptor cells synapse with first-order sensory neurons; located in retina of eye (photoreceptors), inner ear (hair cells), and taste buds of tongue (gustatory receptor cells).