Chps. 18 and 28- Endocrine and Reproductive

Also test 4

what is a hormone

A chemical that is secreted by one cell and travels through the bloodstream to affect the activities of cells in another part of the body.

what is exocrine secretion

secretes into a duct to surface of the body. Ex. sweating

what is endocrine secretion

secretes inside into blood. Ex. Hormones

what is paracrine secretion ?

secretes next to local tissue. Ex. Neurotransmitters

what is autocrine secretion

self secretes, acts on same cell. Cytokines

what are two main groups of hormones? Examples?

• water-soluble; protein hormones, amino acid derivatives

• fat-soluble; steroid hormones, T3, T4

what do fat-soluble hormones require to be transported? Give an example

• Binding globulin (transport protein)

  • Thyroid binding globulin (TBG), transports for T4

what are membrane receptors? what hormone type uses them?

• water-soluble

• they are receptors on the cell membrane on the hormone and this is called first messengers

• they use second messengers (like cyclic AMP) due to their inability to pass the lipid bi-layer of cells. they also cause the activation of a protein

what are intracellular receptors? what hormone type uses them?

• fat-soluble hormones

• they are receptors located within the cell

• the hormone-receptor complex moves to the nucleus to activate protein synthesis

what are Eicosanoids? what are two types?

20-carbon fatty acids derived form essential fat. Referred to as local hormones because they act on neighboring cells (some can have an effect on distant organs)

• prostaglandins

• leukotrienes

what are prostaglandins?

• coordinating local cell activites

• ex. thromboxanes and prostacyclins

what do leukotrinenes do?

• can influence @ a distance. Inflammatory response, blocked by cortisol

examples of Eicosanoids functions

1. formation of platelet plug

2. gastric juice production

3. body temperature control

4. immune functions such as chemotaxis

what are the two parts of the pituitary gland? what is their structure like?

1. Adenohypophysis; anterior pituitary; glandular structure

2. Neurohypophysis; posterior pituitary; nervous structure

how is the adenohypophysis controlled?

• is controlled by releasing and inhibiting hormones from hypothalamus

• releasing hormones enter capillaries of the hypothalamus and travel through hypophyseal portal vein of the infundibulum to reach the anterior pituitary cells

• this stimulates the anterior pituitary to secrete specific hormones

how is the neurohypophysis controlled

• is controlled by neurosecretory cells

• neurosecretory cells have cell bodies in hypopthalamus and axon terminals in posterior pituitary

• axon terminals contain hromones that are released into blood when action potential is sent, potential can be inhibited by receptors in hypothalamus

what are seven water soluble hormones that the adenohypophysis makes

1. thyroid stimulating

2. Adrenocorticotropic

3. follicle stimulating

4. luteinizing

5. melanocyte stimulating

6. human growth

7. prolactin

what are tropic hormones

hormone that acts on another endocrine gland

what are the 4 adenohypophysis hormones that are tropic? what are they regulated by?

1. follicle stimulating

2. luteinizing

3. adrenocorticotropic

4. thyroid stimulating

   1. regulated by hypothalamic-hypophyseal axis

what is the hypothalamic-hypophyseal axis of the thyroid-stimulating hormone?

1. Hypothalamus releases TRH

2. Anterior pituitary gets stimulated by TRH, releases thyroid-stimulating hormone

3. Thyroid gets stimulated, releases T3 and T4

what is the hypothalamic-hypophyseal axis of the adrenocorticotropic hormone?

1. hypothalamus releases CRH

2. anterior pituitary gets stimulated, releases ACTH

3. Adrenal gland, specifically the cortex, gets stimulated. Releasing cortisol

what is the hypothalamic-hypophyseal axis of the follicle-stimulating hormone

1. hypothalamus releases GnRH

2. anterior pituitary gets stimulated, releasing FSH

3. Ovary gets stimulated and releases estrogen and progesterone

what does the Luteinizing hormone (LH) act on? whats the difference between male and females?

• ovary- ovulation

• testes- production of testosterone

what does the follicle stimulating hormone (FSH) act on? whats the difference between male and females?

• ovary- makes eggs

• testes- growth and development of sperm. stimulates release of androgens and progestins

what does Prolactin (PRL) do?

stimulates milk production and maintains milk secretion

what does Melanocyte stimulating hormone (MSH) do?

• stimulates melanocytes of skin

• plays a role in neurochemistry of brain

what does Growth Hormone (hGH) do?

1. increase protein synthesis to stimulate growth of bone and muscle

2. increase blood glucose, liver releases glucose into blood

3. increases lipolysis

what causes some of the effects of hGH?

• Somatomedins, insulin-like growth factors

  • produced by liver

what is gigantism

too much growth hormone as a child

what is pituitary dwarfism

too little growth hormone as a child

what is acromegaly

too much growth hormone as an adult

what two hormones does the neurohypophysis store?

• antidiuretic hormone (ADH)

• Oxytocin (OT)

what is ADH?

Increases water reabsorption in the ascending loop of henle. made when osmotic pressure is high in the blood. it can also cause vasoconstriction when present in high concentration in the blood

what is diabetes insipidus? what signs may you see?

• caused by a lack of ADH

• causes polyuria and hyperosmolarity of the blood due to the inability to reabsorb water

what are the primary target tissues of Oxytocin (OT)

1. smooth muscle of uterus, acts on stretch receptors during labor

2. smooth muscle around ducts in breast, acts on receptors in nipples

what is the purpose of follicular cells in the thyroid?

• they surround a colloid that is filled with thyroglobulin

• they pump iodine into the cell through a ATP run pump so that thyroglobulin and iodine can bind to create T3 and T4

what are the effects of triiodothyronine (T3) and thyroxine (T4)

1. increases metabolism

   1. increases BMR and oxygen rate, increases activity of Na+ and K+ ATPase

2. increases growth and development (primarly bone and nervous development)

3. increases heart rate

congenital hypothyroidism

lack of thyroid hormone as an infant will lead to severe intellectual disability

hypothyroidism

slow heart rate, low body temp, cold sensitive, lethargy

hyperthyroidism/ Graves disease

exophthalmos (abnormal protrusion of one or two eyes)

goiter

enlarged thyroid gland

what is calcitonin? where is it made?

• made by C-cells

• lowers calcium levels in blood by inhibiting osteoclasts

what are the cells that make parathyroid hormone called?

chief cells

how does the parathyroid hormone affect calcium, magnesium and phosphate

• increases calcium levels in blood by activating osteoclasts, promotes calcium reabsorption activates calcitriol production in kidneys (increases calcium absorption in GI)

• increases magnesium in blood

• decreases phosphate in blood

what is the role of vitamin D in calcium reabsorption?

• vitamin D is fat-soluble taken in with food

• it must be activated to calcitriol

• calcitriol then aids in calcium reabsorption in the GI tract

hypoparathyroidism

• lack of parathyroid hormone in blood

• low blood calcium

• signs; tetanic spasms, tetary

hyperparathyroidism

• elevated amounts of parathyroid in blood

• high blood calcium

• signs; high breakdown of bone, kidney stone formation

what layer of the cortex does ACTH primarly act on?

zona fasciculata

what type of hormone does the zona glomerulosa make? example?

• mineralocorticoids (control Na+/K+ levels)

• ex. aldosterone

mineralocorticoids (aldosterone); effects? target tissue? factors that increase it?

• targets kidney tubules

• increases due to angiotensin 2, low Na+ levels, high K+ levels

• increases Na+ reabsorption, increases BP

what type of hormone does the zona fasciculata make? example?

glucocorticoids (hormones that primarily control glucose levels)

ex. cortisol

what type of hormone does the zona reticularis make? example?

gonadocorticoids (hormones that have an effect on ovaries and testes)

ex.androgens

what type of hormones does the adrenal medulla make? ex?

• catecholamines

• ex. epinephrine and norepinephrine

glucocorticoids (cortisol) functions

1. allows handling body stresses

2. catabolic for proteins, fats, and glycogen

3. increases blood pressure (enhances response of blood vessels to other hormones)

4. anti-inflammatory

5. lessens immune response (given to block transplant rejection)

6. slows connective tissue healing by slowing down collagen productionn

hyperaldosteronism signs

high Na+, high blood pressure, low K+

Cushing’s syndrome

too much cortisol

leads to high glucose, poor would healing, fat redistribution, high blood pressure, loss of potassium

Addison’s disease

lack of cortisol

low glucose, high potassium, low blood sodium, and low blood pressure

(an “Addisonian” crisis causes a massive drop in BP, blood sugar, and major electrolight imbalance

gonadocorticoids (androgens)

• in males, low amount of androgens made in zona reticularis

• in females, androgens are converted to estrogens

• play a role in pubertal changes (hair growth) and libido

what stimulates the release of epinephrine and norepinephrine

• sympathetic nervous system, triggers fight or flight

effects of adrenaline (epinephrine) and noradrenaline (norepinephrine)

1. increases metabolism

2. increases blood glucose

3. increases fat breakdown

4. increases heart rate

5. increase blood pressure

6. dilates bronchioles and pupils

pheochromocytoma

• tumor that secretes adrenaline

• causes dangerously high heart rate, high blood pressure, and elevated glucose in blood

what does the alarm phase of stress consist of ?

• includes fight or flight response

• Epinephrine plays a major role

• increases mental alertness, increases energy use of cells, increases heart rate

• decreases digestive and urine functions

what does the resistance (long-term stress) phase of stress consist of ?

• elevated cortisol levels in blood mediate this phase

• high blood suagr due to liver synthesizing

• breakdown of proteins and fats for energy

• high blood pressure

• hGH and TSH promotes lipolysis and increase BMR

what does the exhaustion phase of stress consist of ?

exhaustion, organ failure due to fat reserves being lost

what is the exocrine portion of the pancreas do? what type of acini?

• serous acini

• makes digestive juices and enzymes such as amylase, trypsinogen, lipase, and ribonuclease

what is the endocrine portion of the pancreas do? what is it called?

• islets of langerhans

• has 3 types of cells

  • alpha cells; glucagon

  • beta cells; makes insulin

  • delta cells; makes somatostatins, can inhibit alpha and beta

what is insulin?

• anabolic hormone

• protein, fat and glucose metabolism

• transports glucose into body cells

what stimulates insulin

high blood glucose levels in blood

diabete mellitus

• the inability to use or produce insulin

• signs; polyphagia, polyuria, polydipsia

what is type 2 diabetes/ non-insulin dependent

• insulin that is produced is no longer effective, or insulin cannot be used due to receptor problem or second messenger issue

• poor diet, lack of exercise, insulin resistance

what is type 1 diabetes/ insulin-dependent

• inability of beta cells to produce insulin

• this results in less glucose intake, ketoacidosis can occur

what does estrogen to the ovaries

• regulates menstrual cycle w/help from progesterone

• female secondary sex characteristics

• made in follicular cells

• TSH acts on ovaries to stimulate production of mature egg

what does progesterone do to the ovaries

• controls growth, secretion, and maintenance of endometrium

• maintains pregnancy

what does testosterone do?

• promotes descent of testes

• spermatogenesis

• male secondary sex characteristics

• LH allows increase in testosterone

Thymus purpose

• allows for the maturation of T-cells that travel from bone marrow to cortex of thymus

• Thymosin is the hormone that aids in this process

where is the pineal gland located? what is it’s purpose?

• diencephalon of brain

• secretes melatonin during periods of darkness

  • plays a role in sleep/wake patterns and is an antioxidant

gonads

testes and ovaries

gametes

sperm and eggs

diploid cells

• cells that have homologous pairs of chromosomes

• humans have 23 pairs of homologous chromosomes (46 chromosomes)

  • all cells of the body, except gametes, are diploid

meiosis

cell division that produces sperm and egg through two nuclear divisions resulting in the formation of haploid cells

meiosis 1

each daughter cell receives one chromosome from each homologous pair. the daughter cells have haploid number of duplicated chromosome

meiosis 2

the duplicated chromosomes split at the centromere. resulting in four daughter cells have a haploid number of unduplicated chromosomes

tetrad

a pair of homologous chromosomes

when does spermatogenesis begin?

puberty

what stem cells are involved in spermatogenesis

spermatogonia

what cell goes undergoes meiosis 1 in spermatogenesis? is it haploid or diploid?

• primary spermatocyte

• diploid

in spermatogenesis, what results after meiosis 1? is it haploid or diploid?

• two secondary spermatocytes

• haploid

in spermatogenesis, what cells are formed in meiosis 2? are they haploid or diploid?

• four spermatids

• haploid

spermiogenesis

Spermatids undergo further changes such as loss of cytoplasm, addition of flagellum, mid piece, etc. This turns them into sperm/spermatozoa

in oogenesis, when does the process begin?

3rd prenatal month

in oogenesis, what stem cells are involved?

• oogonia

  • no longer present at birth

in oogenesis, what cell goes undergoes meiosis 1? are they diploid or haploid?

• primary oocyte

  • present at birth in prophase 1 but do not continue meiosis til puberty

• diploid

in oogenesis, what results in meiosis 1? haploid or diploid?

• one secondary oocyte, one polar body

  • secondary oocyte takes all the organelles and cytoplasm, polar body has only 23 chromosomes and is not viable

• haploid

in oogenesis, what cells are formed in meiosis 2 (if ovulated)? haploid or diploid?

• one ovum, 3 polar bodies

  • meiosis 2 only continues after metaphase 2 if ovulated

  • 2 more polar bodies can form from the first if it undergoes meiosis 2 but they al are still not viable

in oogenesis, what happens if fertilization does not occur?

meiosis 2 stops when secondary oocyte reaches metaphase 2

what is the tunica albuginea?

the capsule that surrounds the ovary

how does the broad ligament (w/ mesovarium) stabilize the ovary

attaches ovaries to peritoneum and pelvic cavity

how does the suspensory ligament stabilize the ovary

lateral ovary to open end of uterine tube

how does the ovarian ligament stabilize the ovary

uterine tube to medial surface of ovaries

what is found in the cortex of the ovaries?

primordial follicles