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Homeostasis > Endocrinology and Reproduction > Flashcards

Endocrinology and Reproduction Flashcards

1
Q

Why is the pituitary gland called he master gland?

A

It exercises control over other endocrine glands

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2
Q

Steroid hormones (+example)

A

Steroid hormones:

  • made from cholesterol; lipid soluble
  • Mode of action: diffuse into cells, combine with receptor molecules in cytoplasm - hormone-receptor-complex enters nucleus and attaches to specific part of DNA in a chromosome - activates gene(s) and causes it to synthesize a certain protein
  • ex. sex hormones
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3
Q

Short-term stress response

A

Hypothalamus detects stress; sympathetic nerves
stimulate adrenal medullaEffects of epinephrine and norepinephrine:
-increased blood glucose (glycogen broken down)
-increased blood pressure
-increased breathing rate
-increased metabolic rate
-increased alertness, decreased digestive and kidney activity

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4
Q

Long-term stress response

A

Brain detects stress; ACTHRF produced by hypothalamus; ACTH production by anterior pituitary; hormone production by adrenal cortexEffects of mineralocorticoids:
-retention of Na+ and H2O by kidneys
-increased blood volume and pressure
Effects of glucocorticoids:
-proteins/fats broken down and converted to glucose (increased blood glucose)
-immune system suppressed

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5
Q

State the function and location of the testes

A

Function:
-production of spermatozoa and the hormone testosterone
-testosterone is produced in the interstitial cells of the testes located between the seminiferous tubules
Location:
-in the scrotal sac where there is an optimal temperature for sperm production (2-3 degrees Celsius lower than the normal body temperature)

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6
Q

Endocrine vs. Exocrine glands of the male reproductive system

A

Endocrine Glands:
-ductless glands that secrete hormones into blood (testes)
Exocrine Glands:
-ducted glands that secrete seminal fluid (prostate, seminal vesicles, Cowper’s)

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7
Q

Describe the prostate gland

A
  • produces the prostate fluid
  • thin and alkaline (ensures a buffer for the acidic environment of urethra and vagina)
  • contains a clotting enzyme that converts the protein in seminal fluid into a gelatinous mass (helps protect the sperm from the hostile environment in the vagina)
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8
Q

Describe seminal vesicles

A
  • produces the seminal fluid: thick due to mucus and protein
  • secretes fructose into semen, providing energy for sperm
  • contains prostaglandins: hormones that stimulate contractions of the female reproductive tract (helps move sperm into the oviducts)
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9
Q

Describe the Cowper’s glands (Bulbourethral)

A
  • pair of small oval glands
  • secrete lubricating fluid into the urethra before entering the penis
  • secretions make the sluggish sperm more active
  • help in their passage through the duct system during ejaculation
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10
Q

Name the ducts through which sperm pass to the outside of the body

A
  1. Seminiferous tubules
  2. Epididymis
  3. Sperm duct
  4. Urethra
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11
Q

State the three functions of testosterone in the male

A
  • Initiates the prenatal development of male genitalia
  • Triggers and regulates the development of secondary sexual characteristics
  • Maintains the sec drive in the adult
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12
Q

What is the purpose of the Islets of Langerhams?

A

Detector for negative feedback to regulate blood glucose

  • high bs: beta cells in the pancreas release insulin into the blood, which increases the permeability of cells to glucose
  • low bs: alpha cells release glucagon in the blood, which promotes the conversion of liver glycogen into glucose
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13
Q

In what division of the pituitary gland are hypothalamus hormones ADH and oxytocin stored?

A

Posterior pituitary

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14
Q

State the function of seminal fluid

A
  • provides energy for the sperm

- alkaline to protect the sperm against the acidity of the urethra and vagina

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15
Q

Explain the role of the hypothalamus in controlling the activity of the pituitary gland

A

Hypothalamus produces releasing factors that regulate hormone production in the anterior pituitary (stimulate)

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16
Q

State the function of the ovaries

A
  • secrete estrogen and progesterone

- produce ova

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17
Q

Effects of high levels of T3/T4 (hyperthyroidism)

A

High metabolic rate, feel warm, cannot gain weight

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18
Q

Causes of goitre

A

Inadequate levels of iodine in the diet - thyroxin cannot be produced - no negative feedback to hypothalamus - increased TSH causes enlarged thyroid

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19
Q

Describe the two cycles that make up the menstrual cycle. Why must they be coordinated?

A

Ovarian Cycle
-follicular development leading to ovulation

Uterine cycle
-building up the lining of the uterus for implantation followed by menstruation if pregnancy does not occur

*The two cycles must be coordinated in order to ensure that the endometrium is prepared for implantation when a fertilized ovum reaches the uterus

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20
Q

State the function of the epididymis

A
  • storage structure in each testis where sperm mature and become motile
  • sperm can be stored for about a month before losing their fertility
  • sperms do not make use of their swimming ability until they are ejaculated
  • a healthy sperm can swim up to 4 mm per minute
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21
Q

State the function of seminal fluid

A
  • provides energy for the sperm

- alkaline to protect the sperm against the acidity of the urethra and vagina

22
Q

State the role of GnRH, FSH, and LH in spermatogenesis

A

GnRH

  • gonadotropin-releasing hormone
  • secreted by the hypothalamus in sexually mature males in brief pulses every 1-2 hours
  • stimulates the pituitary gland to release FSH and LH

FSH
-initiates sperm production at puberty
-maintains sperm production and growth of Sertoli cells needed to nourish developing sperm
(Sertoli cell production is regulated by negative feedback; secretions inhibit FSH production)

LH
-stimulates interstitial cells (Leydig cells) to produce testosterone
(testosterone is regulated by negative feedback; inhibits GnRH and LH production AND stimulates Sertoli cells to secrete inhibin, which reduces FSH secretion)

23
Q

State the function of the ovaries

A

-secrete estrogen and progesterone

24
Q

State the function of the oviducts

A
  • transport ova to the uterus

- site of fertilization

25
Q

State the function of the uterus including endometrium

A
  • lining (known as endometrium) thickens in preparation for the implantation of the embryo
  • embryo then develops into fetus and then newborn
26
Q

State the function of the cervix

A
  • at the junction of the uterus and vagina

- stretching occurs during menstruation and childbirth (partuition)

27
Q

State the function of the vagina

A

Functions in childbirth and intercourse

28
Q

Describe the two cycles that make up the menstrual cycle. Why must they be coordinated?

A

Ovarian Cycle
-follicular development leading to ovulation

Uterine cycle
-building up the lining of the uterus for implantation followed by menstruation if pregnancy does not occur

*The two cycles must be coordinated in order to ensure that the endometrium is prepared for implantation when a fertilized ovum reaches the uterus

29
Q

Key hormones in female reproductive system

A

FSH (released from anterior pituitary)

  • stimulates growth of follicle
  • stimulates secretion of estrogen

ESTROGEN (released from follicle cells)

  • stimulates repair and growth of endometrium
  • negative feedback on pituitary to block FSH release
  • feedback on pituitary to release LH

LH (released from anterior pituitary)

  • stimulates ovulation
  • stimulates conversion of empty follicle to corpus luteum
  • stimulates secretion of estrogen and progesterone from corpus luteum

PROGESTERONE (released from corpus luteum)

  • stimulates final growth of endometrium
  • negative feedback on pituitary blocking FSH
  • negative feedback on pituitary blocking LH
30
Q

Describe the corpus cavernosum

A
  • two parallel masses of sponge-like tissues
  • made up of smooth muscle and blood vessels
  • begin at pelvic bone and extend just below head of penis
  • spongy tissue fills with blood from arteries down the length of the penis
  • expands to hold 90% of blood involved in an erection
31
Q

Describe the corpus spongiosum

A
  • spongy tissue in the penis surrounding the urethra
  • prevents urethra from closing during erection
  • without it, it would be impossible for semen to pass through the penis during ejaculation
32
Q

Outline the phases of Gametogenesis

A
  1. Multiplication
    -gamete mother cells divide by mitotic cell division to produce many cells with the potential to become gametes
  2. Growth
    -developing sex cells undergo growth
  3. Maturation
    -involves meiosis and produces haploid gametes
    Meiosis I: produces secondary spermatocytes/oocytes
    Meiosis II: produces spermatids and ova
33
Q

Distinguish between Spermatogenesis and Oogenesis

A

Spermatogenesis:

  • spermatogonia formed from puberty until death
  • all spermatogonia develop into sperm cells; nurtured by nutritive cells in seminiferous tissues
  • 100 to 200 million sperm are formed daily (entire process takes 64 days)
  • 4 sperm formed per spermatogonium
  • sperm released by ejaculation
  • Meiosis I and II go to completion
  • small mobile gametes
  • both testis produce sperm

Oogenesis

  • oogonia formed in embryonic ovaries before birth; stops at menopause
  • many oogonia fail to develop and degenerate
  • surrounded by follicle cells to form primary follicles and remain dormant in cortex
  • only a few primary oocytes undergo meiosis to become secondary oocytes and only one forms a Graffian follicle each month
  • one ovum is formed from each oogonium (polar bodies degenerate)
  • Graffian follicle releases secondary oocyte into oviduct
  • Meiosis reaches prophase II and then stops until a male nucleus enters the secondary oocyte
  • fertilized ovum implants in the endometrium and embryo forms
  • ovulations tends to occur from alternative ovaries every month
34
Q

Describe follicle development and ovulation

A
  • follicles: fibrous connective tissue and small group of cells in ovaries
  • follicles contain primary oocytes and granulosa cells
  • Primary oocytes undergo meoisis
  • Granulosa cells provide nutrients for the oocyte
  • when nutrient cells divide, the follicle enlarges
  • ovulation releases the secondary oocyte from the follicle
35
Q

How does the corpus luteum form? State its function.

A
  • follicle cells that remain after ovulation transform into the corpus luteum
  • secretes estrogen and progesterone to maintain the endometrium and prevent ovulation and uterine contractions
36
Q

Name and describe the four phases of the menstrual cycle

A
  1. FLOW (menstruation):
    - 1 to 5 days
    - endometrium sheds
    - weak uterine contractions
  2. FOLLICULAR
    - 6 to 13 days
    - follicle develops
    - secretion of estrogen
    - endometrium thickens
  3. OVULATION
    - 14 days
    - secondary oocyte is released from follicle
    - remaining follicular cells form the corpus luteum
  4. LUTEAL
    - 15 to 28 days
    - endometrium continues to develop
37
Q

What is the Canadian hormone?

A
  • Atrial natriuretic peptide, found in the atria of the heart
  • lowers blood volume and pressure caused by renin-angiotensin-aldosterone system
  • generates sodium loss
  • increased urine output
  • secreted when there is atrial distention from increased blood volume
38
Q

State the site of production and function of progesterone

A
  • produced by the corpus luteum
  • promotes development of the endometrium
  • negative feedback feedback to anterior pituitary and hypothalamus to inhibit FSH and LH secretion
  • prevents ovulation and further follicle development
39
Q

State the site of production and function of progesterone

A
  • produced by the corpus luteum
  • promotes development of the endometrium
  • negative feedback feedback to anterior pituitary and hypothalamus to inhibit FSH and LH secretion
  • prevents ovulation and further follicle development
40
Q

What hormonal changes trigger ovulation?

A

Rising LH and decreasing FSH resulting from an increase in estrogen

41
Q

What is the most abundant hormone produced by the ant/ pituitary?

A

Growth Hormone/Somatotropin

42
Q

Function of adrenal medulla

A
  • when stimulated by sympathetic (fight or flight) nerves in times of stress, releases epinephrine and norepinephrine, which:
  • increase blood glucose
  • dilate blood vessels
  • dilate iris
  • SHORT TERM stress response
43
Q

Function of adrenal cortex (glucocorticoids and mineralocorticoids)

A
  1. release glucocorticoids (cortisol), which:
    - increases amino acids in blood, to be used for energy or protein synthesis
    - helps body recover from stress
  2. release mineralocorticoids (aldosterone), which:
    - increase Na+ reabsorption in distal tubule and collecting ducts to help maintain water balance (increases blood pressure)
    - LONG TERM stress response
44
Q

Function of adrenal cortex (glucocorticoids and mineralocorticoids)

A
  1. release glucocorticoids (cortisol), which:
    - increases amino acids in blood, to be used for energy or protein synthesis
    - helps body recover from stress
  2. release mineralocorticoids (aldosterone), which:
    - increase Na+ reabsorption in distal tubule and collecting ducts to help maintain water balance (increases blood pressure)
45
Q

What role do prostoglandins play in the repsonse to stress?

A
  • 16 types
  • stimulated by epinephrine
  • 2 types adjust blood flow during stress
  • others respond to stress by triggering the relaxation or constriction in bronchial airways
  • released during allergic reactions and during childbirth
46
Q

What are synthetic steroids?

A
  • mimic the actions of natural steroids
  • ex. anabolic steroids mimic the muscle-building characteristics of testosterone
  • also have legitimate medical usages (suppressing immune system after transplants)
  • commonly used to treat arthritis, asthma and lupen (ex. hydrocortisone for inflammatory skin disorders (for ur cyst this is what i was saying!!)
47
Q

Describe the 3 classes of performance-enhancing rugs and give and example for each.

A

1) Anabolic steroids: increase muscle mass and strength
Side effects - decreased growth, kidney problems, hair loss, oily skin, acne, shrinking testes, infertility, cancer
ex. Stanozolol, androstenediol, nandrolone
2) Peptide hormones: decreases fat and improves muscle mass; increases RBC (carry more oxygen)
Side effects - diabetes, bone, liver, heart, kidney abnormalities, liver disease, high BP; thickens blood, heart problems and stroke
ex. growth hormone, erythropoietin (EPO)
3) Masking agents: makes steroids difficult to detect; temporarily stops excretion of steroids
Side effects: can cause headache, tissue swelling, nausea
ex. bromantan, probenecid

48
Q

Stages of Spermatogenesis

A

1) Spermatogonia (2n) divide endlessly by mitosis to produce more spermatogonia (2n)
2) Spermatogonia grow into larger cells with more cytoplasm called primary spermatocytes (2n)
3) Each primary spermatocyte carries out the first division of meiosis to produce two secondary spermatocytes (n)
4) Each secondary spermatocyte carries out the second division of meiosis to produce two spermatids (n)
5) Spermatids become associated with Sertoli cells, which help them develop into spermatozoa (n) (cell differentiation)
6) Sperm detach from Sertoli cells and eventually are carried out of the testis by the fluid in the centre of the seminiferous tubule and moves to EPIDIDYMIS

49
Q

Stages of Oogenesis

A

1) In the ovaries oogonia (2n) divide by mitosis to from more oogoniga (2n)
2) Oogonia grow into larger cells, primary oocytes (2n)
3) Primary oocytes start the first division of meiosis but stop at prophase I. the primary oocyte and a single layer of follicle cells form a primary follicle (ovary contains 400 000 with a girl)
4) Every menstrual cycle a few primary follicles start to develop. The primary oocyte completes the first division of meoisis, forming two haploid nuclei. The cytoplasm of the primary oocyte is divided unequally forming a large secondary oocyte in (n) and a small polar (n)
5) The secondary oocyte starts the second division of meiosis but stops in prophase II. follicular fluid forms
6) When the mature follicle bursts, the egg is released still as a secondary oocyte
7) After the fertilization the secondary oocyte completes the second division of meiosis to form an ovum, and a second polar cell. The first and second polar bodies degenerate.

50
Q

Stages of Fertilization

A

1) Arrival of sperm
- sperm are attracted by chemical signal and swim to oviduct to reach the egg
2) Binding
- the first sperm breaks through follicles and binds to zona pellucida
3) Acrosome reaction
- contents of the acrosome are released by the separation of the acrosomal cap from the sperm
- it’s proteases make a route for sperm through the zona pellucida to reach the plasma membrane of the egg
4) Fusion
- The plasma membranes of the sperm and egg fuse and the sperm nucleus enters the egg and joins the egg nucleus
- Fusion causes the cortical reaction
5) Cortical Reaction
- Small vesicles called cortical granules move to the plasma membrane of the egg and fuse with it, releasing their contents by exocytosis
- Enzymes from the cortical granules cause cross-linking of glycoproteins in the zona pellucida, making it hard and preventing entry of any more sperm

Homeostasis (3 decks)

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