BIOM1060 Lecture Notes - Lecture 41: Secondary Sex Characteristic, Anterior Pituitary, Posterior Pituitary

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orangeshark166

16 Jun 2018

School

Department

Biomedical Science

Course

BIOM1060

Professor

James Cuffe

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BIOM1060 29/05/18

REPRODUCTIVE ANATOMY

Endocrine system in reproduction

- Reproduction controlled by hormones

- Hypothalamus

→ anterior pituitary → ovaries, testes, uterus and breast

→ posterior pituitary → uterus and breast

Nervous system in reproduction

- Reproductive responses (esp. sexual activity)

Reproductive physiology in males

- Hormones regulate sperm production, testosterone production and secondary sexual

characteristics

- Male sexual response predominantly driven by neural control (eg. erection, ejaculation)

Regulation of sex hormones in males

- Hypothalamus: gonadotropin releasing hormone (GnRH)

- Anterior pituitary gland: follicle stimulating hormone (FSH) and luteinizing hormone (LH)

o FSH: stimulates sperm production, supported by Sertoli cells

o LH: stimulates testosterone production in Leydig cells

- Testes: sperm and testosterone

Testosterone

- Regulates physiological changes related to: hair growth, strength, aggression, vocal

changes, cognition and the reproductive system

- Regulates libido, supports spermatogenesis and promotes muscle build up

- Increases enzymes eNOS and nNOS activity (both produce nitric oxide required for

erection)

- Levels increased through sexual activity

- Reduced by metabolic syndrome/diabetes

- Low testosterone = erectile dysfunction

Spermatogenesis

- Mitotic proliferation: produces large number of cells

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BIOM1060 29/05/18

- Meiotic division: generates half chromosomes

- Cytodifferentitation (spermiogenesis): packages chromosomes for delivery to oocyte

Sertoli cells

- Maintain environment that supports sperm production

- Form blood testis barrier (immunological and physical protection for sperm)

- Release compounds when stimulated by FSH which promotes meiosis

- Produce inhibin hormone (homeostatic feedback which inhibits FSH production)

Lifespan of sperm

- Formation of spermatogonia to mature sperm: ~64 days

- Take 12-26 days to travel through epididymis

- Fertilising ability up to 48hrs after ejaculated

Ejaculate/semen

- 10% sperm

- 70% seminal vesicles (high fructose content that power mitochondria of sperm)

- 20% bulbourethral, prostatic and epididymal fluid

- Not uniform (first to exit = highest in sperm content)

Physiological regulation of the sexual response

- Four step process: excitement, plateau, orgasm, resolution

Erection

- Flaccid penis: arterioles supplying erectile tissue constricted

- Erection established through neural input (regulate pudendal arteries/arterioles)

o Parasympathetic response triggers release of nitric oxide (relaxes smooth muscle

in vessels → vasodilation → engorgement)

o Sympathetic innervation drives flaccidity

o Somatic innervation: innervation of striated muscles

Male sexual response

- Bulbourethral gland stimulated by parasympathetic to release lubrication

- Nitric oxide release stimuli:

o Reflexogenic: mechanical stimuli - sacral spinal reflex (still occur if spinal cord

severed above T12)

o Psychogenic: visual, auditory, olfactory or tactile (still occur if spinal cord severed

above lumbar region)

Emission

- Movement of ejaculate into prostatic urethra

- Caused by parasympathetic neural input and contraction of vas deferens smooth muscle,

seminal vesicles and prostate

- Urethral sphincter closes (prevent backflow into bladder)

- Retrograde ejaculation: occurs if sphincter does not close (causes infertility)

Ejaculation

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Document Summary

Anterior pituitary ovaries, testes, uterus and breast. Hormones regulate sperm production, testosterone production and secondary sexual characteristics. Male sexual response predominantly driven by neural control (eg. erection, ejaculation) Anterior pituitary gland: follicle stimulating hormone (fsh) and luteinizing hormone (lh: fsh: stimulates sperm production, supported by sertoli cells, lh: stimulates testosterone production in leydig cells. Regulates physiological changes related to: hair growth, strength, aggression, vocal changes, cognition and the reproductive system. Regulates libido, supports spermatogenesis and promotes muscle build up. Increases enzymes enos and nnos activity (both produce nitric oxide required for erection) Mitotic proliferation: produces large number of cells. Cytodifferentitation (spermiogenesis): packages chromosomes for delivery to oocyte. Form blood testis barrier (immunological and physical protection for sperm) Release compounds when stimulated by fsh which promotes meiosis. Produce inhibin hormone (homeostatic feedback which inhibits fsh production) Formation of spermatogonia to mature sperm: ~64 days. Take 12-26 days to travel through epididymis. Fertilising ability up to 48hrs after ejaculated.

Related Questions

From the list below, select all statements accurate with respectto hormonal regulation of steroid hormone production in males andfemales.

Question 9 options:

A)	hypothalamic secretion of GnRH stimulates LH and FSH secretionin the anterior pituitary

B)	FSH secretion in the anterior pituitary stimulates testosteronesecretion in theca cells and Leydig cells

C)	FSH secretion in the anterior pituitary stimulates inhibinsecretion by granulosa cells and Sertoli cells of the ovary andtestis, respectively

D)	LH secretion stimulates testosterone secretion in both ovariangranulosa and theca cells

E)	LH secretion stimulates testosterone secretion in Leydig andtheca cells of the testes and ovaries, respectively

F)	inhibin feeds back to turn down both LH and FSH secretion in theanterior pituitary

G)	inhibin feeds back to selectively suppress LH secretion in theanterior pituitary without changing FSH secretion

H)	inhibin feeds back to selectively suppress FSH secretion in theanterior piutitary without changing LH secretion

I)	testosterone secretion in males always feeds back to inhibitGnRH secretion from the hypothalamus

J)	testosterone secretion in males always feeds back to inhibitanterior pituitary responsiveness to GnRH

K)	progesterone in high concentration has an inhibitory effect onGnRH secretion in the hypothalamus

L)	similar to testosterone's effect in males, estrogen in femalesalways feeds back to inhibit GnRH secretion from thehypothalamus

M)	when estrogen levels in females are low, estrogen feeds back atthe hypothalamus to inihibit GnRH secretion from the hypothalamussimilar to testosterone's effects in males

N)	when estrogen levels in females are high and unaccompanied byhigh progesterone levels, estrogen is stimulatory, rather thaninhibitory to GnRH secretion in the hypothalamus

O)	if estrogen levels in females are high but are accompanied byhigh progesterone levels, the powerful inhibitory effects ofprogesterone override the stimulatory effects of estrogen andsuppress GnRH secretion from the hypothalamus

viridianhornet587

Match each hormone with its corresponding action.

ACTH, ADH, FSH, STH (GH), LH, MSH, OCT, PRL, TSH

A. Stimulates egg and sperm formation in ovaries and testes.

B. Targets pigmented cells in skin and other surface coverings; induces color changes in response to external stimuli and affects some behaviors.

C. Stimulates and sustains milk production in mammary glands.

D. Stimulates progesterone secretion, ovulation, and corpus luteum formation in females; promotes testosterone secretion and sperm release in males.

E. Induces uterine contractions and milk movement into secretory ducts of the mammary glands.

F. Stimulates release of thyroid hormones from the thyroid gland.

G. Acts on kidneys to conserve water required in control of extracellular fluid volume.

H. Stimulates release of adrenal steroid hormones from the adrenal cortex.

I. Promotes growth in young; induces protein synthesis and cell division; has roles in adult glucose and protein metabolism.

taupealpaca895

Please help me answer this multiple choice questions: (please answer all questions)

No explantion needed just the answer needed.

physiology and neurobiology questions below.

31. Systemic arterioles dilate in response to _____.

A. Increased CO2 levels in the tissue

B. Decreased O2 levels in the tissue

C. Decreased pH in the tissues

D. All of the above

32. Blood in the pulmonary arteries ______

A. Contains hemoglobin which is about 98.5% saturated with oxygen

B. Has a PO2 of about 40 mmHg

C. Both of the above

D. Neither of the above

33. Completion of first meiotic division of oogenesis yields.

A. One secondary oocyte

B. Four primary oocyte

C. Four mature ova (egg cells)

D. Four secondary oocytes

34. The final absorbable products of chemical digestion occurring in the brush border of the small

intestine include:

A. Monosaccharides and amino acids

B. Proteins and chylomicrons

C. Disaccharides and amino acids

D. Monosaccharides and disaccharides

35. The hemoglobin oxygen curve saturation curve plots ____ on the dependent (Y) axis and ____

on the independent (X) axis.

A. Oxygen concentration; hemoglobin concentration

B. % oxygen saturation of hemoglobin; PO2 of blood

C. % oxygen saturation of hemoglobin; PCO2 of blood

D. Hemoglobin concentration; oxygen concentration

36. In contrast to the female hypothalamic pituitary-sex steroid axis, control of the male axis is

aimed at ____.

A. Allowing spermatogenesis to occur just once a month

B. Keeping levels of pituitary gonadotropins relatively constant in blood

C. Keeping levels of hypothalamic releasing hormones higher than usual in blood

D. Causing a positive feedback effect of sex steroid up on gonadotropins

37. Which of the following will correct acidosis?

A. Speed up the proton pump

B. Buffering of protons with phosphate in the tubular lumen

C. Renal metabolism of glutamine

D. All of the above

38. Epithelium with a brush border (microvilli) is characteristics of the mucosa found in

A. Duodenum

B. Proximal Tubule

C. Both of the above

D. Neither of the above

39. The transport maximum (Tm) for glucose, addition filtered glucose

A. Is no longer filtered

B. Appears in urine

C. Is secreted

D. Is reabsorbed

40. Stroke volume is equal to ____.

A. End-diastolic volume alone

B. End-diastolic volume plus end-systolic volume

C. Cardiac output minus heart rate

D. End-diastolic volume minus end-systolic volume

41. The long term solution to a change in blood pH involves

A. Digestive System

B. Respiratory System

C. Buffers such as hemoglobin

D. Renal System

42. The left heart receives blood from ___ and pumps blood out through the ____.

A. Superior vena cava; pulmonary trunk

B. Pulmonary veins, pulmonary trunk

C. Pulmonary veins; aorta

D. Pulmonary arteries; aorta

43. Selection and activation of specific B lymphocytes may lead to all EXCEPT_____.

A. Formation of memory cells

B. Secretions of antibodies

C. Activation of complements to destroy tagged antigen

D. Secretion of perforin

44. Bile is stored and released into the duodenum from the

A. Liver

B. Pancreas

C. Gall Bladder

D. Duodenum

45. Beta oxidation of fatty acids yields _____,which then can be further oxidized to produces ATP.

A. Glycogen

B. Amino acids

C. Keto acids

D. Acetyl CoA

46. The relationship between the loop of Henle and the vasa recta capillaries function.

A. Absorption of glucose, amino acids and creatinine

B. Countercurrent exchange

C. Countercurrent multiplication

D. All of the above

47. Anterior pituitary production of Follicle Stimulating Hormone (FSH) is decreased by

A. Testosterone from Sertoli cells

B. Inhibin from Sertoli cells

C. Inhibin from interstitial (Leydig) cells

D. Luteinizing Hormone (LH) from granulosa cells

48. A response to acidosis would involve

A. Slowing down the proton pump

B. Greatly increased excretion of HCO3- (bicarbonate ions)

C. Both of the above

D. Neither of the above

49. The conversion of spermatid to spermatozoa occurs

A. By differentiation process in the seminiferous tubule

B. In epididymis

C. By meiosis, in the seminiferous tubule

D. In the prostate gland

50. Antibody-mediated immunity defends against ____.

A. Virus infected cells

B. Viruses and bacteria in the blood or body fluids

C. Bacteria only

D. Viruses only

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BIOM1060 Lecture Notes - Lecture 41: Secondary Sex Characteristic, Anterior Pituitary, Posterior Pituitary

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