• Paired oval glands in the scrotum

• About 5 cm long and 2.5 cm in diameter

• Each testis (singular) has a mass of 10-15 grams.

• Spermatogenesis occurs in the seminiferous tubules.

The scrotum:

Normal sperm production requires the temperature about ?°C below core body temperature.

The scrotum:

The location of the scrotum and the contraction of its muscle fibers regulate the ? of the testes.

Reproductive system ducts in males:

• Alternative name is vas deferens.

• Conveys sperm during sexual arousal from the epididymis towards the urethra by peristaltic contractions of its muscular coat.

• Like the epididymis, the ductus deferens also can store sperms for several months.

The accessory sex glands secrete most of the liquid portion of semen. Include:

1. the seminal vesicle,

2. the prostate,

3. the bulbourethral gland

Seminal fluid

• Events in the ovaries

1. Under the influence of FSH, several primordial follicles develop into primary follicles and then into secondary follicles.

2. This developmental process may take several months to occur.

3. Therefore, a follicle that begins to develop at the beginning of a particular menstrual cycle may not reach maturity and ovulate until several menstrual cycles later.

• Events in the ovaries

1. Some of the secondary follicles in the ovaries begin to secrete estrogens and inhibin.

2. By about day 6, a single secondary follicle in one of the two ovaries has outgrown all of the others to become the dominant follicle.

3. Estrogens and inhibin secreted by the dominant follicle decrease the secretion of FSH.

4. Other less well-developed follicles stop growing and undergo atresia.

5. Normally, the one dominant secondary follicle becomes the mature (graafian) follicle, which continues to enlarge until it is more than 20 mm in diameter and ready for ovulation.

6. This follicle forms a blister-like bulge due to the swelling antrum on the surface of the ovary.

7. During the final maturation process, the mature follicle continues to increase its production of estrogens.

• Events in one ovary

1. After ovulation, the mature follicle collapses, and the basement membrane between the granulosa cells and theca interna breaks down.

2. Theca interna cells mix with the granulosa cells as they all become transformed into corpus luteum cells under the influence of LH.

3. Stimulated by LH, the corpus luteum secretes progesterone, estrogens, relaxin, and inhibin.

• Events in the uterus

1. Menstrual flow from the uterus consists of 50-150 mL of blood, tissue fluid, mucus, and epithelial cells shed from the endometrium.

2. This discharge occurs because the declining levels of progesterone and estrogens stimulate release of prostaglandins that cause the uterine spiral arterioles to constrict.

3. As a result, the cells they supply become oxygen-deprived and start to die.

4. Eventually, the entire stratum functionalis sloughs off.

5. At this time the endometrium is very thin, about 2-5 mm, because only the stratum basalis remains.

• Events in the uterus

1. Estrogens liberated into the blood by growing ovarian follicles stimulate the repair of the endometrium.

2. Cells of the stratum basale undergo mitosis and produce a new stratum functionalis.

3. As the endometrium thickens, the short, straight endometrial glands develop, and the arterioles coil and lengthen as they penetrate the stratum functionalis.

4. The thickness of the endometrium approximately doubles, to about 4-10mm.

• Events in the uterus

1. Progesterone and estrogens produced by the corpus luteum promote growth and thickening of the endometrium to 12-18 mm (0.48-0.72 in.).

2. These preparatory changes peak about 1 week after ovulation, at the time a fertilized ovum might arrive in the uterus.

3. If fertilization does not occur, the levels of progesterone and estrogens decline due to degeneration of the corpus luteum.

4. Withdrawal of progesterone and estrogens causes menstruation.

First week:

Fertilization normally occurs in the uterine (fallopian) tube 輸 卵管within ? hours after ovulation.

First week:

Thus, pregnancy is most likely to occur if intercourse takes place during a ?-day window — from ? days before ovulation to ? day after ovulation.

First week:

A sperm cell must penetrate two layers:

Second week:

The trophoblast secreted ? , which has structure & actions similar to LH.

Second week:

? rescues corpus luteum from degeneration and sustains its secretion progesterone and estrogens.

Second week:

Soon, a small cavity appears within the epiblast 外胚層 and eventually enlarges to form the ? cavity.

Second week:

? serves as a shock absorber for the fetus

• helps regulate fetal body temperature,

• helps prevent the fetus from drying out,

• prevents adhesions between the skin of the fetus and surrounding tissues.

Second week:

The extraembryonic mesoderm and the two layers of the trophoblast forms the ?.

Second week:

Connecting stalk - the future ?.

Third week:

As the embryo develops, the ? ultimately becomes the epithelial lining of the gastrointestinal tract, respiratory tract, and several other organs.

Third week:

The ? gives rise to muscles, bones, and other connective tissues, and the peritoneum.

Third week:

The ? develops into the epidermis of the skin and the nervous system.

Third week:

forebrain

Third week:

midbrain

Third week:

hindbrain

Third week:

develops into the telencephalon and diencephalon

Third week:

develops into the metencephalon and myelencephalon

Third week:

develop into the skeletal muscles of the neck, trunk, and limbs.

Third week:

form connective tissue, including the dermis of the skin.

Third week:

give rise to the vertebrae and ribs.

Third week:

forms the heart and the visceral layer of the serous pericardium, blood vessels, the smooth muscle and connective tissues of the respiratory and digestive organs, and the visceral layer

of the serousmembrane 漿膜 of pleurae 胸膜 and peritoneum腹膜.

Third week:

gives rise to the bones, ligaments, blood vessels, and connective tissue of the limbs and the parietal layer 頂層 of the serous membrane of the 心包 pericardium, pleurae, and peritoneum.

Third week:

formed by the chorionic villi of the chorion

Third week:

formed by the decidua basalis of the endometrium

Third week:

can be frozen to provide a future source of pluripotent stem cells 多能幹細胞, for example, to repopulate red bone marrow following radiotherapy for cancer.

Prenatal diagnostic tests:

amniocentesis

Prenatal diagnostic tests:

Chorionic sampling (CVS)

Maternal changes during pregnancy:

? produced first by the corpus luteum of the ovary and later by the placenta.

• Increases the flexibility of the pubic symphysis.

• Helps dilate the uterine cervix, pubic symphysis 恥骨聯合 and ligaments 韌帶 of the sacroiliac 骶髂關節and sacrococcygeal joints 骶尾部關節 during labor.

• Both of these actions ease delivery of the baby.

Maternal changes during pregnancy:

• The chorion 絨毛膜 begins to secrete ? after the first 3 or 4 weeks of pregnancy and progesterone by the 6th week.

Maternal changes during pregnancy:

• A high level of ? ensures that the uterine myometrium is relaxed and that the cervix is tightly closed.

Maternal changes during pregnancy – Physiological changes:

? due to the fetus, amniotic fluid, the placenta,

uterine enlargement, and increased total body water.

Maternal changes during pregnancy – Physiological changes:

? of proteins, triglycerides, and minerals for

fetal growth and development.

Maternal changes during pregnancy – Physiological changes:

? due to rising concentrations of

estrogen, progesterone and prolactin in preparation for lactation.

Maternal changes during pregnancy – Physiological changes:

? : During pregnancy, the ligaments naturally

become softer and stretch to prepare for labour. This can put

a strain on the joints of the lower back and pelvis, which can

produce back pain.

Maternal changes during pregnancy – Physiological changes, Cardiovascularsystem:

? (amount of blood ejected from the ventricle with each cardiac cycle) increases by about 30%.

Maternal changes during pregnancy – Physiological changes, Cardiovascularsystem:

? (=heart rate X stroke volume) rises by 20–30% to provide mother and fetus with nutrients and oxygen through a larger blood flow.

Maternal changes during pregnancy – Physiological changes, Cardiovascularsystem:

? increases 10–15%.

Maternal changes during pregnancy – Physiological changes, Cardiovascularsystem:

? increases 30–50%, mostly during second 1/2 of pregnancy

Maternal changes during pregnancy – Physiological changes, Cardiovascularsystem:

Compression of the renal artery can lead to renal ?.

Maternal changes during pregnancy – Physiological changes, Respiratory system:

? (amount of air that moves in/out of lungs with each respiratory cycle) can increase by 30-40% to meet increased oxygen requirement

Maternal changes during pregnancy – Physiological changes, Respiratory system:

? (extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration) can be reduced by up to 40%

Maternal changes during pregnancy – Physiological changes, Respiratory system:

? (volume remaining in the lungs after a normal, passive exhalation) can decline by up to 25% due to compression of the diaphragm by the uterus.

Maternal changes during pregnancy – Physiological changes, Respiratory system:

? (the total volume of air inhaled and exhaled per minute) can increase by up to 40% partly due to effect of progesterone

Maternal changes during pregnancy – Physiological changes, Respiratory system:

? (resistance of the respiratory tract to airflow during inhalation and exhalation) in the bronchial tree can decline by 30-40% due to hormonally induced relaxation of tracheobronchial tree smooth muscles

Maternal changes during pregnancy – Physiological changes, Digestive system:

? in appetite due to the added nutritional demands of the fetus.

Maternal changes during pregnancy – Physiological changes, Digestive system:

A general ? in GI tract motility due to growing uterus pressing on the GI tract can :

• Cause constipation;

• Delay gastric emptying time;

• Produce nausea, vomiting, and heartburn

Maternal changes during pregnancy – Physiological changes, Urinary system:

Increased ? of urination, and stress incontinence due to increased pressure from growing uterus.

Maternal changes during pregnancy – Physiological changes, Urinary system:

An increase in ? up to 35%.

Maternal changes during pregnancy – Physiological changes, Urinary system:

An increase in ? up to 40%.

Maternal changes during pregnancy – Physiological changes, Urinary system:

An increase in renal plasma flow up to 35%. An increase in glomerular filtration rate up to 40%.

That is, increased ?.

Maternal changes during pregnancy – Physiological changes, Urinary system:

Allows faster ? wastes produced by the foetus.

Maternal changes during pregnancy – Physiological changes, Changes in skin:

Increased pigmentation around the eyes and cheekbones - ?

Maternal changes during pregnancy – Physiological changes, Changes in skin:

Increased ? in the areolae (circular dark-colored area of skin surrounding the nipple) of the breasts, and in the linea alba of the lower abdomen (linea nigra) due to increased hormones.

Maternal changes during pregnancy – Physiological changes, Changes in skin:

? (stretch marks) over the abdomen due to the rapid rate at which the skin is being stretched, combined with the influence of hormones.

Labor (parturition):

Towards the end of gestation, the levels of ? in the mother’s blood rise sharply, producing changes that overcome the inhibiting effects of progesterone.

Labor (parturition), The rise in estrogens results from:

• Increasing secretion by the placenta of ?

Labor (parturition), The rise in estrogens results from:

CRH stimulates the anterior pituitary gland of the fetus to secrete ?

Labor (parturition), The rise in estrogens results from:

ACTH stimulates the fetal adrenal gland to secrete cortisol and ?

Labor (parturition):

• High levels of ? cause the number of receptors for oxytocin on uterine muscle fibres to increase and cause uterine muscle fibres to form gap junctions with one another.

Labor(parturition):

? (hypothalamic peptide stored in and) released by the posterior pituitary stimulates uterine contractions.

Labor(parturition):

? from the placenta assists by increasing the flexibility of the pubic symphysis and helping dilate the uterine cervix.

Labor(parturition):

? also stimulates the placenta to release prostaglandins, which induce production of enzymes that digest collagen fibres in the cervix, causing it to soften.

Labor(parturition):

? feedback control (amplifying the original action) :

• Contraction of the uterine myometrium forces the baby’s head into the cervix.

• Stretching of the cervix stimulates stretch receptors.

• Stretch receptors send signals to neurosecretory cells in hypothalamus.

• Oxytocin is released.

• Oxytocin stimulates more forceful contraction of the myometrium.

Adjustment of infants at birth:

The fetus is stressed during childbirth, which are compressed?

1. head

2. umbilical cord

3. placenta

Adjustment of infants at birth, Cardiovascular adjustments:

Closure of ? between the atria of the fetal heart occurs at birth.

Adjustment of infants at birth, Cardiovascular adjustments:

Once the lungs begin to function, the ? shuts off due to smooth muscle contractions of its wall, and it becomes the ?

The control of lactation:

• The principal hormone in promoting milk production.

• Secreted from the anterior pituitary gland.

The control of lactation:

• It causes milk release into mammary ducts via the milk ejection reflex.

• Milk formed by the glandular cells of the breasts is stored until the baby begins active suckling.

During late pregnancy and the first few days after birth, the mammary glands secrete a cloudy fluid called ?.

Breast milk contains, Beneficial cells:

? also produce lysozyme and other immune system components.

Breast milk contains, Beneficial cells:

? develop from B lymphocytes, produce antibodies against specific microbes.

Breast milk contains, Beneficial cells:

? kill microbes directly or help mobilise other defences.

Male puberty:

Which is the first sign of puberty?

Female puberty:

Which is the first sign of puberty?

Aging-associated physiological changes:

Skin becomes ?. The loss of the elastic tissue in the skin with age causes the skin to hang loosely.

Aging-associated physiological changes:

Skin becomes more ?. This is caused by thinning of the epidermis (surface layer of the skin).

Aging-associated physiological changes:

Skin becomes more ?. This is caused by a flattening of the area where the epidermis and dermis (layer of skin under the epidermis) come together.

Aging-associated physiological changes:

Skin becomes more ? due to thinner blood vessel walls.

Aging-associated physiological changes, Skeletal System:

Age-related loss in skeletal muscle mass and strength, known as ?. results in a decrease in mobility and independence, as well as an increase in the risk of other morbidities and mortality.

Functions performed by kidneys:

Production of hormones

active form of vitamin D (increase calcium absorption in the intestine) – calcium homeostasis

Renal circulation:

1. Aorta

2. Renal artery

3. Segmental artery

4. Interlobar artery

5. Arcuate artery

6. Cortical radiate artery

7. afferent arteriole

Renal circulation:

1. inferior vena cava

2. Renal vein

3. Interlobar vein

4. Arcuate vein

5. Cortical radiate vein

6. Peritubular capillaries or vasa recta

7. Efferent arteriole

Renal circulation:

1. afferent arteriole

2. glomerulus

3. efferent arteriole

Internal anatomy of nephron:

where blood plasma is filtered

Internal anatomy of nephron:

which the filtered fluid (glomerular filtrate) passes

Glomerular filtration:

1. Glomerular filtration

2. Tubular reabsorption

3. Tubular secretion

Glomerular filtration:

• cells are having large fenestrations(0.07-0.1um in diameter) → Leaky nature

• Allow all solutes to pass out EXCEPT blood cells.

• fenestrated capillaries that allows solute-rich, virtually protein-free filtrate to pass from the blood into the glomerular capsule

Glomerular filtration:

• a layer between the endothelial cells and the podocytes.

• is made of collagen fibers and negatively-charged glycoproteins. → repel proteins which are mostly negatively charged

• This prevents proteins from being filtered into the filtrate.

Glomerular filtration:

• (foot processes from podocytes) wrap around the glomerular capillaries. Slit membrane is present between pedicels to prevent nearly all proteins from passing through. This permits molecules with diameter smaller than 0.006-0.007 um.

• Therefore, water, glucose, vitamins, amino acids, ammonia, urea, different ions and very small size plasma proteins can pass through.

GFR Decrease with:

1. Dehydration

2. Low blood pressure

3. Overhydration

4. Chronic kidney disease

5. Increased age

GFR Increase with:

1. Dehydration

2. Low blood pressure

3. Overhydration

4. Chronic kidney disease

5. Increased age

Androgens (Testosterone and dihydrotestosterone):

▪ At puberty, development and enlargement of the male sex organs.

▪ Development of masculine secondary sexual characteristics.

Androgens (Testosterone and dihydrotestosterone):

▪ Testosterone: development of reproductive system ducts and descent of the testes into the scrotum.

Androgens (Testosterone and dihydrotestosterone):

▪ Contribute to male sexual behaviour and spermatogenesis.

▪ Sex drive (libido) in both males and females.

Androgens (Testosterone and dihydrotestosterone):

▪ Androgens stimulate protein synthesis, heavier muscle and bone mass in men.

• A single, doughnut-shaped gland about the size of a golf ball.

• The prostate slowly increases in size from birth to puberty.

• It then expands rapidly until about age 30, after such time its size typically remains stable until about age 45, when further enlargement may occur.

• Secretes a milky, slightly acidic fluid (pH about 6.5)

• Or Cowper’s glands

• About the size of peas.

• Secrete an alkaline fluid during sexual arousal into the urethra.

• Protect the passing sperms by neutralizing acids from urine in the urethra.

• Secrete mucus that lubricates the end of the penis and the lining of the urethra, decreasing the number of sperms damaged during ejaculation.

• is a mixture of sperm and seminal fluid.

• Consists of the secretions of the seminiferous tubules, seminal vesicles, prostate, and bulbourethral glands.

• The volume of semen in a typical ejaculation is 2.5-5 millilitres (mL), with 50-150 million sperms per mL.

• Slightly alkaline

Prostate:

(prostate-specific antigen (PSA), pepsinogen, lysozyme, amylase, and hyaluronidase): break down the clotting proteins from the seminal vesicles.

Functions of the female reproductive system:

produce secondary oocytes and hormones, including progesterone and estrogens (female sex

hormones), inhibin, and relaxin.

Functions of the female reproductive system:

transport a secondary oocyte to the uterus and normally are the sites where fertilization occurs.

Functions of the female reproductive system:

is the site of implantation of a fertilized ovum, development of the foetus during pregnancy, and labour.

Functions of the female reproductive system:

receives the penis during sexual intercourse and is a passageway for childbirth.

Functions of the female reproductive system:

synthesize, secrete, and eject milk for nourishment of the newborn.

• A modified sudoriferous (sweat) gland that produces milk.

• consists of 15 to 20 lobes.

• In each lobe are several smaller compartments called lobules, composed of grape-like clusters of milk- secreting glands termed alveoli (= small cavities).

• When milk is produced, it passes from the alveoli into a series of secondary tubules and then into the ducts.

• Near the nipple, the ducts expand slightly to form the lactiferous sinuses, where some milk may be stored before draining into a lactiferous duct.

• The function of the mammary glands.

• Lactation includes the synthesis, secretion, and ejection of milk.

• Associated with pregnancy and childbirth.

• Milk production is stimulated largely by the hormone prolactin from the anterior pituitary, with contributions from progesterone and estrogens.

• The ejection of milk is stimulated by oxytocin, which is released from the posterior pituitary in response to the sucking of an infant on the mother’s nipple (suckling).

Hormones from corpus luteum:

▪ Secreted mainly by the corpus luteum.

▪ Cooperates with estrogens to prepare and maintain the endometrium for implantation of a fertilized ovum.

▪ Prepares the mammary glands for milk secretion.

▪ High levels of progesterone also inhibit secretion of GnRH and LH.

Hormones from corpus luteum:

▪ Produced by the corpus luteum in a small quantity.

▪ Relaxes the uterus by inhibiting contractions of the myometrium. During pregnancy, the placenta produces much more relaxin, and it

continues to relax uterine smooth muscle.

▪ At the end of pregnancy, relaxin increases the flexibility of the pubic symphysis and may help dilate the uterine cervix, ease delivery.

Hormones from corpus luteum:

▪ Secreted by granulosa cells of growing follicles and by the corpus luteum after ovulation.

▪ It inhibits secretion of FSH and, to a lesser extent, LH.

Third week – Development of the chorionic villi and placenta:

Can AIDS, German measles, chickenpox, measles, encephalitis, and poliomyelitis cross the placenta?

Teratogen:

1. Alcohol

2. Cocaine

3. LSD

4. Therapeutic drugs

5. Viruses

6. Cigrette smoking

7. Irradiation

Prenatal diagnostic tests:

• To determine a more accurate fetal age when the date of conception 受孕日期is unclear.

• To confirm pregnancy.

• To evaluate fetal viability 胎兒活力 and growth.

• To determine fetal position.

• To identify multiple pregnancies.

• To identify fetal–maternal abnormalities.

• To serve as an adjunct to special procedures such as amniocentesis

Prenatal diagnostic tests, Non-invasive Alternatives:

• Developed by a scientist in Hong Kong.

• Now used for detection of genetic disorders.

• Determination of sex of fetus.

Prenatal diagnostic tests, Non-invasive Alternatives:

• High AFP is an indication of neural development problems in the fetus such as spina bifida 脊柱裂, a condition in which the bones of the spine don’t close around the spinal cord, or anencephaly 無腦畸形, a condition in which the brain does not develop properly

Adjustment of infants at birth, Respiratory adjustments:

• A full-term baby may breathe ? times per minute for the first 2 weeks after birth.

• Breathing rate gradually declines until it approaches a normal rate of ? breaths per minute.

The control of lactation, Prolactin:

• The impulses ? hypothalamic release of prolactin-inhibiting hormone (PIH) and ? release of prolactin-releasing hormone (PRH), so more prolactin is released by the anterior pituitary.

Breast-feeding:

1. Decreased incidence of diseases later in life.

2. Ideal for the baby’s digestion, brain development, and growth.

3. supports optimal infant growth,

4. Premature infants benefit even more

5. less likely to have an allergic reaction

Aging-associated physiological changes, Blood:

• Blood volume

• haemoglobinconcentration

• White cell count

• Concentrations of major electrolytes are unaffected by age (except

for a tendency for the mean serum calcium)

Aging-associated physiological changes, Cardiovascular System:

• in maximum heartrate

• Blood vessels elastic. Less flexibility, stiffness, and thickening of the aorta

Aging-associated physiological changes, Respiratory system:

• Vital capacity (the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath)

• elasticity of the lungs & in respiratory muscular strength

Aging-associated physiological changes, Nervoussystem:

• Number of neurons in some parts of the nervous system (e.g. motor neurons of the spinal cord & cells of the substantia nigra).

• number of neurons & connections between them → Alterationsin cortical function.

• Neurotoxic amyloid beta peptide deposits forming plaques around brain cells. Hyperphosphorylated tau protein deposits of forming neurofibrillary tangles within brain cells. Degeneration of cholinergic neurons that produces the neurotransmitter acetylcholine.

• Increased memory loss and confusion

• Inability to learn new things

• Shortened attention span

• Problems coping with new situations

• Difficulty organizing thoughts and thinking logically

• Difficulty with language and problems with reading, writing, and working with numbers

• Cell death in the substantia nigra 黑質that produces the neurotransmitter dopamine多巴胺.

• Tremor, stiffness, bradykinesia, and difficulty with balance and coordination.

Nephrons and collecting duct:

• Glomerulus

• Glomerular (Bowman’s) capsule

Nephrons and collecting duct:

• Proximal convoluted tubule

• Nephron loop (Loop of Henle)

– Descending limb

– Ascending limb

• Distal convoluted tubule

Nephrons and collecting duct:

▪ a series of tubes that carry tubular fluid away from the nephron

Tubularreabsorption:

? -> Tight junction -> Interstitial fluid

Tubularreabsorption:

? -> Apical membrane -> Cytosol -> Basolateral membrane ->Interstitial fluid

Net Filtration Pressure = ? – ? – ?

1. glomerular hydrostatic pressure

2. blood osmotic pressure

3. capsular hydrostatic pressure

Renin-angiotensin system:

• Water reabsorption ? the blood volume, hence ? the blood pressure.