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Biol 233 > Exam 4: Digestive & Reproductive > Flashcards

Exam 4: Digestive & Reproductive Flashcards

1
Q

Large Intestine Functions

A

H2O Absorption

Feces Transportation

NO Nutrient Absorption

Full of Bacteria

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2
Q

Haustrum

A

“Bulbs” of the Large Intestine

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3
Q

Ileocecal Valve

A

Allows chyme to enter the Cecum

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4
Q

Structures of the Anal Canal

A

Rectal Valve: Prevents feces from passing with flatus (gas)

External Anal Sphincter: Skeletal muscle under voluntary control

Internal Anal Sphincter: Smooth muscle under involuntary control

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5
Q

Ileoanal Juncture

A

If the LI is removed (due to cancer or other complications), the Ileum is connected to the anus. When this happens, H2O cannot be reabsorbed, thus diet must be modified.

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6
Q

Bacterial Flora in the Large Intestine

A

Bacteria enter from the Small Intestine or Anus, colonizing in the Colon

Bacteria ferment indigestible carbohydrates, release irritating acids and gases, and synthesize B complex vitamins and vitamin K

If the bacteria enter the blood, it could lead to death

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7
Q

Haustral Contractions

A

Segmentation contractions that occur at random

Not like Peristaltic Contractions, which are wave-like from one end to the other

Haustral Contractions are good for mixing the contents of the LI and they occur slowly to allow surface area contact, promoting more H2O reabsorption

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7
Q

Functions of contractions in the small intestine

A

Mixes chyme with intestinal juice to neutralize acid and digest nutrients more effectively

Churns chyme to allow contact with mucosa for contact digestion & nutrient absorption

Moves residue toward the large intestine

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7
Q

Neural Control of Defecation

A

Stretch receptors in the Sigmoid Colon send signals to the spinal cord

The spinal cord stimulates a reflex that contracts the rectum and relaxes the internal sphincter

The brain can keep the external sphincter contracted until it is appropriate or until the rectum stretches too much

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8
Q

Intestinal Motility

A

Segmentation occurs in the Small Intestine until only undigested residue remains. At this point, peristaltic contractions begin to move the residue to the Large Intestine

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9
Q

Microvilli in the Small Intestine

A

Extensions of the intestine wall cells that increase surface area, thus increasing contact with intestinal contents. They promote more secretion and absorption. Contact digestion breaks macros down into their simplest forms then absorption can occur

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10
Q

Carbohydrate Digestion

A

Starches & Disaccharides are ingested

Salivary Amylase begins digestion in the mouth

Pancreatic Amylase digests in the small intestine

Macromolecules are broken down into Oligosaccharides & Disaccharides

Brush Border Enzymes in the SI break Oligosaccharides & Disaccharides into Lactose, Maltose, & Sucrose

Lactose & Sucrose are broken down into Galactose, Glucose, & Fructose

Glucose, Galactose, & Fructose enter the bloodstream

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11
Q

Protein Digestion

A

Proteins are ingested

Pepsin breaks proteins into smaller polypeptides in the stomach

Polypeptides enter the Small Intestine

Pancreatic Enzymes such as Trypsin & Chymotrypsin break polypeptides into smaller oligopeptides

Carboxypeptidase removes one amino acid at a time from the end of an oligopeptide

Brush Border Enzymes in the SI break small peptides & polypeptides into amino acids, dipeptides, & tripeptides

Amino Acids enter the bloodstream

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12
Q

Fat Digestion

A

Fats are ingested

Fat globules have pieces of Bile Acid that stick to it, breaking the globule into smaller droplets

Pancreatic Enzyme lipase digests the triglyceride droplets, creating free fatty acids and monoglycerides

FFAs & Monoglycerides are coated with Bile Salts to form Micelles. Micelles are the smallest forms of fats before absorption via diffusion

In the SI epithelium, FFAs & Monoglycerides are either combined into Triglycerides or Chylomicrons and released

After diffusion, FFAs & Monoglycerides recombine into chylomicrons, which enter lacteals (lymph vessels) which carry the fats away from the intestine

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13
Q

Nucleic Acid Digestion

A

Nucleic Acids are ingested, go through the stomach, and enter the Small Intestine

Pancreatic Ribonuclease & Deoxyribonuclease break down RNA & DNA in the SI

Brush Border Enzymes break Nucleic Acids down further into Pentose sugars, N-containing bases, & Phosphate ions

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14
Q

Vitamin Absorption

A

In the small intestine:
- Fat-soluble vitamins (A, D, E, & K) diffuse into absorptive cells
- Water-soluble vitamins (C & B) are absorbed by diffusion or via passive or active transporters
- Vitamin B12 binds with intrinsic factor & is absorbed by endocytosis

In the large intestine
- Vitamin K & B vitamins are absorbed via bacterial metabolism

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15
Q

Gametes

A

Sex cells produced by each parent

They are unique compared to every other cell in the body

Sperm & Eggs are Haploid, containing only 1/2 of the genetic information each

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16
Q

Male Secondary Sex Characteristics

A

Facial hair, coarse & visible hair on the torso & limbs, relatively muscular physique

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17
Q

Female Secondary Sex Characteristics

A

Distribution of body fat, breast enlargement, and relatively hairless appearance of the skin

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18
Q

Secondary Sex Characteristics of Both Sexes

A

Pubic & Axillary Hair & associated Scent Glands, Pitch of the voice

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19
Q

Androgen-Insensitivity Syndrome

A

An XY-carrying individual will have testes present in the abdomen at birth which produce a normal level of testosterone. The target cells, however, lack receptors for it. This results in female genitalia developing as if no testosterone is present. The individual will not menstruate or develop a uterus.

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20
Q

Chromosomal Sex Determination

A

22 pairs of autosomes
1 pair of sex chromosomes

Males produce half Y-carrying sperm and half X-carrying sperm
Females carry all X-carrying eggs (NO Y)

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21
Q

Prenatal Sexual Differentiation

A

Gonads begin to develop at 5-6 weeks, before that there is no sexual differentiation

Estrogen does not determine sex

The lack of androgen (testosterone) causes female development in the fetus

The male urethra gets longer around 7-8 weeks

Around birth, the testes flip downward in males but remain up in the body to form ovaries in females

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22
Q

Male Reproductive Anatomy

A

Scrotum: Hangs outside the body because sperm production can only occur at temperatures lower than the body’s core

Epididymis: Storage compartment for sperm

Vas Deferens: Peristaltic contractions occur to propel sperm to the urethra

Ejaculatory Duct: The duct where sperm enters the urethra. NOT URINARY DUCT

Corpus Cavernosum: Erectile Tissue that sits on the top side of the penis. 2 columns

Corpus Spongiosum: Erectile Tissue that surrounds the urethra

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23
Q

The Musculature of the Scrotum

A

Cremaster: Contracts in response to cold, drawing the testes upward toward the body

Dartos Fascia: Wrinkles the scrotum to minimize the surface area in contact with the cold

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24
Q

Countercurrent Heat Exchange

A

Warm blood flowing into the testes exchanges heat with the colder venous blood. The temperature drops 1.5-2.5 degrees C before reaching the testes. This allows for the testes to be at the optimal temperature for sperm production

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25
Q

Spermatic Ducts

A

Duct of the Epididymis: Site of sperm maturation & storage. If not ejaculated, they disintegrate and are reabsorbed by the epididymis

Ductus Deferens: A long muscular tube passing from the scrotum through the inguinal canal to the posterior surface of the bladder. At the end, it connects with the duct of the seminal vesicle. NO sperm production or storage, just transportation

Ejaculatory Duct: A short duct that passes through the prostate and empties into the urethra

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26
Q

Sperm Production Time

A

It takes roughly 18 hours to make new sperm and fill the epididymis

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27
Q

Vasectomy

A

Cutting of the Vas Deferens which prevents sperm from reaching the urethra or exiting the body

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28
Q

Semen is made of what?

A

60% comes from the seminal vesicles (sperm)
30% comes from the prostate (a milky substance that activates sperm)
10% comes from the bulbourethral glands (lubricant that neutralizes acidic urine and the acidic nature of the vaginal canal)

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29
Q

How do sperm become mobile?

A

The substance produced by the seminal vesicles is high in sugar. The sperm metabolizes this sugar to produce ATP. The ATP is then used to allow sperm movement.

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30
Q

Erectile Tissues

A

Corpus Cavernosum: Fills with blood to cause an erection

Corpus Spongiosum: Fills with blood to keep the urethra open. When blood isn’t present, the tissue is like a deflated balloon, closing the urethra to semen flow.

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31
Q

Reproductive System Dormancy

A

The reproductive system doesn’t become active in boys until 10-12 y.o. and 8-10 y.o. in girls

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32
Q

Adolescence

A

The period from the onset of gonadotropin secretion and reproductive development to when a person attains full adult height

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33
Q

Puberty

A

The first few years of adolescence, until the first menstrual period in girls or the first ejaculation of viable sperm in boys

Typically around 14 in boys and 12 in girls

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34
Q

Puberty Changes in Males

A

Growth of sex organs (penis, testes, scrotum, ducts, glands)

Testosterone stimulates generalized body growth (limbs elongate, muscle mass increases, larynx enlarges)

Erythropoiesis, Basal Metabolic Rate, & Appetite increase

Pubic hair, axillary hair, & facial hair develop in response to Dihydrotestosterone (DHT)

Sperm production & libido are stimulated

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35
Q

Hormone Release with Male Maturity

A

GnRH is released from the Hypothalamus at a higher rate with maturity

GnRH stimulates the Anterior Pituitary to release Follicle Stimulating Hormone & Luteinizing Hormone

FSH activates Androgen-Binding Proteins within Nurse Cells

LH affects interstitial cells

ABP causes cells to “listen” to testosterone

Interstitial Cells release Testosterone

Testosterone, when combined with ABP, induces spermatogenesis

Spermatogenic Cells produce Inhibin, which inhibits the release of FSH & LH, reducing Testosterone levels

Too much Testosterone inhibits the Ant. Pituitary from releasing FSH and LH until Testosterone is low enough to maintain homeostasis

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36
Q

Aging & Sexual Function

A

Testosterone secretion declines with age. Peak secretion is at age 20 and secretion is 1/5 of that value by age 80. This occurs due to the decline in the number and activity of interstitial endocrine cells.

Andropause: Male climacteric. A period of declining reproductive function starting in the 50s

The age-related drop in Testosterone and inhibin triggers a rise in FSH & LH, potentially causing mood swings and hot flashes

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37
Q

Spermatogenesis Meiosis

A

Results in 4 unique daughter cells

Before Prophase I, there is a diploid cell with 92 chromosomes

Prophase I: Crossing Over produced genetic variability (beneficial for preventing diseases)
Metaphase I: Chromosomes are lined up along the center
Anaphase I: Chromosomes are pulled apart
Telophase I: 2 unique daughter cells are formed, each being haploid

Prophase II: Chromosomes are housed in their cells
Metaphase II: Chromosomes align along the center
Anaphase II: Chromosomes are pulled apart, leaving only sister chromatids
Telophase II: 4 unique haploid cells are produced, each with single-stranded chromosomes

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38
Q

Spermatogenesis Cell Types

A

Type A spermatogonia go through Mitosis to make more diploid cells

Type B spermatogonia go through Meiosis I & II

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39
Q

Spermiogenesis

A

The process that takes place after Meiosis II has been completed. It is the process where sperm develop tails

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40
Q

Spermatocyte Movement during Spermatogenesis

A

Once primary spermatocytes undergo meiosis, they become genetically different and require protection from the immune system

The primary spermatocyte moves toward the lumen of the seminiferous tubule and a tight junction forms between the nurse cells behind it

These tight junctions protect the spermatocytes from being attacked by the immune system (Blood-Testis Barrier)

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41
Q

Sperm Anatomy

A

Acrosome: During development, it wraps around the nucleus and forms a tip. It has chemical receptors that can “smell” its way to the eggs. Contains enzymes that penetrate the egg

Head: The pear-shaped leading portion of the sperm that houses the nucleus and acrosome.

Midpiece: A thicker cylindrical portion of the tail that houses the mitochondria

Mitochondria: Metabolize sugars from the substance produced by the seminal vesicles, forming ATP

Flagellum: The tail of the sperm that allows for mobility

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42
Q

Sperm Counts

A

Normal Sperm Count 50-120 million/mL

Infertility occurs with a count lower than 20-25 million/mL

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43
Q

Requirements For Semen/Sperm Motility

A

Two requirements for the movement of sperm are elevated pH and an energy source

The substance from the prostate buffers vaginal acidity from 3.5 to 7.5 pH
The prostate provides fructose & other sugars to the mitochondria of sperm for ATP production

The substance from the seminal vesicles also produces prostaglandins, which thin the mucus of the cervical canal and stimulate waves of contractions

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44
Q

How does an erection occur & what are the effects of Viagra?

A

Sexual stimulation triggers a spike in nitric oxide

Nitric oxide leads to the activation of cGMP

cGMP increases blood flow to the erectile tissue

cGMP will degrade over time due to the presence of PDE5, leading to the erection going away

Viagra inhibits the actions of PDE5, allowing the erection to occur and remain

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45
Q

STD Carriers

A

STDs are only effective and produce symptoms when large amounts of pathogens are present

Individuals can be carriers yet show no signs or symptoms, as their body has not yet recognized the pathogen

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46
Q

Bacterial STDs

A

Chlamydia: may cause urethral discharge and testicular pain

Gonorrhea: pain & pus discharge; may result in sterility from pelvic inflammatory disease

Syphilis: hard lesions (chancres) at the site of infection

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47
Q

Viral STDs

A

Genital Herpes: The most common STD in the US, results in blisters and pain

Genital Warts: Warts on the perineal region, cervix, & anus caused by HPV

Hepatitis B & C: Inflammatory liver disease

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48
Q

What are ovaries?

A

Female gonads that produce egg cells (ova) & sex hormones

Outer cortex where germ cells develop

The inner medulla is occupied by major arteries & veins

Each egg develops in its own fluid-filled follicle

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49
Q

Uterine Tubes

A

AKA Oviducts or Fallopian Tubes, they are canals roughly 10 cm long from the ovaries to the uterus

They are muscular tubes lined with ciliated cells and are highly folded into longitudinal ridges

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50
Q

Grades of Cervical Cancer

A

Class I: Mild Dysplasia
Class II: Biopsy Required
Class III: Results from Biopsy may call for radiation therapy or hysterectomy

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51
Q

Layers of the Uterine Wall

A

Perimetrium: External Serosa Layer
Myometrium: Middle Muscular Layer
Endometrium: Inner Mucosa

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52
Q

Myometrium of the uterus

A

The muscular layer that constitutes most of the uterine wall

Made of mostly smooth muscle

Produces labor contractions to expel the fetus

More fibrous near the cervix

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53
Q

Endometrium of the uterus

A

Functional Layer: Superficial half of the endometrium that is shed with each menstrual cycle

Basal Layer: Deep half of the endometrium that stays behind to regenerate a new functional layer after each menstrual cycle

During pregnancy, the endometrium is the site of attachment for the embryo and forms the maternal part of the placenta for fetal nourishment

54
Q

Vaginal Epithelium Cell Types & Functions

A

Undergoes metaplasia: During childhood, the tissue is simple cuboidal and changes to stratified squamous after puberty

Bacteria in the epithelium ferment glycogen to produce the acidic pH of the vagina. This acidic nature inhibits the growth of pathogens

The epithelium has antigen-presenting dendritic cells

55
Q

External Genitalia of Women

A

Collectively called the vulva or pudendum

Mons Pubis: the mound of fat over the pubic symphysis that bears most of the pubic hair

Labia Majora: A pair of thick folds of skin and adipose tissue inferior to the mons. Composed of the same tissue as the scrotum

Labia Minora: Thin, hairless folds medial to the labia major

Clitoris: Erectile sensory organ, the primary center for sexual stimulation

Vestibular Bulbs: Erectile tissue deep to the labia major

Greater & Lesser Vestibular & Paraurethral Glands open into the Vestibule for Lubrication

56
Q

Mammary Glands

A

Develops during pregnancy and remains active in the lactating breast

Atrophies when a woman ceases to nurse

The areolar nerve fibers trigger the milk ejection reflex

57
Q

Breast Cancer

A

A leading cause of female mortality, breast cancer occurs in 1 of 8-9 women

Tumors begin with cells from mammary ducts and may metastasize by mammary & axillary lymphatics

Most breast cancer is hereditary, though the BRCA1 & 2 genes contribute to some cases. Some cases are also stimulated by estrogen

58
Q

Breast Cancer Treatment

A

Lumpectomy: Removal of the tumor only

Simple Mastectomy: Removal of breast tissue only or sometimes breast tissue and some axillary lymph nodes

Radial Mastectomy: Removal of the breast, underlying muscle, fascia, and lymph nodes

Surgery is followed by radiation or chemotherapy

59
Q

Puberty in Women

A

Puberty begins at age 8-10 for most US girls

Triggered by rising levels of GnRH, stimulating the Ant. Pituitary to secrete FSH & LH

60
Q

Puberty Hormones in Women

A

GnRH stimulates the secretion of FSH & LH

FSH stimulates ovarian follicles

Ovarian Follicles begin to secrete estrogen, progesterone, inhibin, & a small amount of androgen

61
Q

Signs of Puberty in Women

A

Thelarche: Breast development triggered by estrogen, progesterone, & prolactin

Pubarche: Pubic & axillary hair development along with their sebaceous & axillary glands. This change is stimulated by androgens

Menarche: The first menstrual period stimulated by gonadotropin secretion. Leptin from body fat stimulates gonadotropin secretion; if body fat or leptin levels drop, so does gonadotropin, leading to a halt in the menstrual cycle

62
Q

Estradiol in Puberty

A

Stimulates the growth of ovaries & secondary sex organs

Stimulates growth hormone secretion

Stimulates fat deposition

Suppresses FSH & LH secretion

63
Q

Progesterone in Puberty

A

Acts on the uterus to prepare it for possible pregnancy

Suppresses FSH & LH secretion

64
Q

Oogenesis

A

The development of a single-cell egg

65
Q

Reproductive Cycle

A

The sequence of events from fertilization to giving birth and returning to fertility

66
Q

Sexual Cycle

A

The sequence of events that recur every month when pregnancy doesn’t intervene

Consists of both the Ovarian & Menstrual Cycles

67
Q

Embryonic Development of the Ovary

A

Female germ cells arise from the yolk sac & colonize the gonadal ridges during the first 5-6 weeks of development

These cells differentiate into oogonia & multiply until the 5th month (roughly 6-7 million cells are produced)

Most oocytes degenerate by the time a girl is born

By puberty, 200,000 oocytes remain

Meiosis occurs early on in development and then stops

68
Q

Egg Development in Adolescence

A

At birth, only primary oocytes are present in the body. FSH stimulates roughly 24 oocytes to complete meiosis I each month

After meiosis I, a secondary oocyte and the first polar body are produced

If the secondary oocyte is not fertilized, it dies. If it is fertilized, the secondary oocyte goes through meiosis II, producing an ovum and the second polar body

Shortly after completing meiosis II, the ovum DNA is joined with the sperm DNA to form a zygote

Sometimes the polar bodies will divide before dying, which is where the 4 daughter cells come from

69
Q

Follicle Development in Adolescence

A

Primordial Follicles are produced during fetal development

In adolescence, the primary follicles begin to have granulosa cells grow around the outside of the oocyte

After more development, the zona pellucida (extracellular coat) forms between the granulosa cells and the oocyte, becoming the secondary follicle

The zona pellucida grows further, forming the antrum, a larger fluid-filled layer between the tunica interna and oocyte. This is the tertiary follicle

During ovulation, the now-mature follicle bursts, sending the oocyte into the uterine tube. The follicle wall remains in the ovary, becoming the corpus luteum

70
Q

Phases of Folliculogenesis

A

Follicular Phase: Period of follicle growth (days 1-14) where the selected follicle(s) grow

Ovulation occurs mid-cycle, releasing the secondary oocyte from the ovary

Luteal Phase: Period of corpus luteum activity (days 14 - 28)

71
Q

What is the Antrum

A

A fluid-filled pocket in the middle of the follicle which helps with the bursting of the follicle during ovulation. A spike in LH causes the antrum to swell, leading to this burst

72
Q

Hierarchy of Hormonal Control in Women

A

Hypothalamus

Pituitary

Ovaries: The ovaries can also inhibit the hormones from the hypothalamus & pituitary via feedback control

Uterus

73
Q

The Female Sexual Cycle

A

Before the start of menstruation, the Ant. Pituitary is secreting a lot of FSH, which is “choosing” the next oocyte

Once an oocyte or two is selected, FSH is suppressed by the follicle to prevent many oocytes from developing at once

Once the follicle matures, it releases higher levels of estradiol. At a certain point, the estradiol causes a spike in LH, which in turn triggers the swelling and bursting of the follicle’s antrum

After ovulation, the corpus luteum remains for 7-8 days, secreting hormones to keep FSH and LH low to allow for implantation

If no implantation occurs, FSH rises again

74
Q

Follicular Phase of the Ovarian Cycle

A

The follicular phase occurs over the first 14 days after menstruation

FSH stimulates follicles to grow and secrete estradiol

The chosen (dominant) follicle becomes increasingly sensitive to FSH, LH, & Estradiol

The follicle, as it matures, secretes some estradiol, which stimulates the Ant. Pituitary to release more LH & less FSH, leading to ovulation

LH also causes the primary oocyte to complete meiosis I

75
Q

Signs of Ovulation

A

Cervical mucus becomes thinner and more stretchy

Resting body temperature rises by 0.4-0.6 degrees F

Mittelschmerz: Twinges of pain at the time of ovulation

The best time for conception is within 24 hours of these signs

76
Q

Luteal Phase of the Ovarian Cycle

A

The luteal phase occurs through days 15-28 after the onset of menstruation

LH stimulates the corpus luteum to grow and secrete rising levels of estradiol & progesterone

Progesterone suppresses FSH and prepares the uterus for implantation

FSH & LH secretion declines over the rest of the cycle

If fertilization occurs, the resulting embryo releases chemicals to keep the corpus luteum from shrinking

When involution occurs, progesterone and inhibin levels drop, resulting in FSH levels rising again

77
Q

Phases of the Menstrual Cycle

A

Proliferative Phase: Rebuilding of the Functional Layer

Secretory Phase: Thickening of the Endometrium caused by Progesterone

Premenstrual Phase: Endometrial Degeneration

Menstrual Phase: Discharge of Menstrual Fluid from the Vagina

78
Q

Proliferative Phase of the Menstrual Cycle

A

A new cohort of follicles develops, secreting more estrogen

Estrogen stimulates mitosis in the basal layer as well as regrowth of blood vessels, both of which act to regenerate the functional layer

79
Q

Secretory Phase of the Menstrual Cycle

A

Thickening of the endometrium due to secretions & fluid buildup

Endometrial glands secrete glycogen (sugar) for the potential embryo

80
Q

Premenstrual Phase of the Menstrual Cycle

A

The corpus luteum atrophies, causing endometrial ischemia (interrupting blood flow) where the vessels are pinched off before the functional layer

Causes tissue necrosis & menstrual cramps

81
Q

Menstrual Phase (menses) of the Menstrual Cycle

A

Discharge of menstrual fluid from the vagina

The first day of discharge is day 1 of the new cycle

82
Q

Hormones during the Menstrual Cycle

A

Just before ovulation, during the proliferative phase, estradiol spikes greatly, and progesterone slightly

After ovulation, the secretory phase begins. Here, estradiol drops due to the bursting of the follicle. Progesterone spikes, keeping estradiol from falling too low. In this phase, nutrition is added to the endometrium, causing the layer to thicken.

If no implantation occurs, the endometrium is killed and the corpus luteum shrinks, causing progesterone and estradiol levels to fall

The falling off of estradiol and progesterone causes the beginning of a new menstrual cycle

83
Q

Implantation of the Zygote

A

If fertilization occurs, implantation will sometimes result. When implantation occurs, the embryo will enter the grooves of the endometrium and get covered up

84
Q

Endometriosis

A

The growth of endometrial tissue outside of the uterus

Growth is often on the peritoneum of the pelvic cavity or on the surface of the ovary

Occurs in 6-10% of women

Causes pain and sometimes infertility

Believed to result from retrograde menstruation: backward flow of menstrual fluid through the uterine tubes

85
Q

Stages of Female Sexual Response

A

Unstimulated

Excitement

Plateau

Orgasm

Resolution

86
Q

Unstimulated Stage of Female Sexual Response

A

The uterus tilts forward over the urinary bladder

The vagina is relatively narrow

The labia minora is retracted

87
Q

Excitement Stage of Female Sexual Response

A

The uterus stands more superiorly with the inner end of the vagina dilated, it is no longer laying against the bladder

The labia minora becomes vasocongested, extending beyond the labia major

The labia minora and vaginal mucosa become red/violet due to hyperemia

Vaginal transudate moistens the vagina & vestibule

88
Q

Plateau Stage of Female Sexual Response

A

The uterus begins tenting: moving up and down into the vaginal canal to contact any potential semen

The orgasmic platform (lower 1/3) of the vagina constricts the penis

The clitoris is engorged and its glans is withdrawn beneath the prepuce

89
Q

Orgasm Stage of Female Sexual Response

A

The orgasmic platform contracts rhythmically

The cervix may dip into the pool of semen

The uterus exhibits peristaltic contractions

Anal & urinary sphincters constrict

90
Q

Resolution Stage of Female Sexual Response

A

The uterus returns to its original position

The orgasmic platform relaxes

The inner end of the vagina constricts & returns to its original dimensions

91
Q

Female Orgasm

A

An intense sensation that spreads from the clitoris through the pelvis

Pelvic throbbing & a spreading sensation of warmth

The pelvic platform gives 3-5 strong contractions

The cervix plunges spasmodically into the vagina

Involuntary pelvic thrusts may occur late in the plateau phase

Paraurethral glands sometimes expel copious fluid (female ejaculation)

92
Q

Gestation

A

Pregnancy which lasts an average of 266 days from conception to childbirth

Birth is predicted to be 280 days from the last menstrual period

93
Q

Terms for a zygote throughout gestation

A

Weeks 1-2: Conceptus

Weeks 3-8: Embryo

Weeks 9-12: Fetus

94
Q

Umbilical Cord & Placenta Development

A

The umbilical cord & placenta show up around week 9, starting relatively small

95
Q

Time requirements for fertilization

A

The oocyte is viable for 12-24 hours

Sperm is viable 24-48 hours after ejaculation

For fertilization to occur, coitus must occur no more than 2 days before or 24 hours after ovulation

96
Q

What happens to ejaculated sperm?

A

Leaks out of the vagina immediately after deposition

Destroyed by the acidic vaginal environment

Fail to make it through the cervix

Dispersed into the uterine cavity via peristaltic contractions or destroyed by phagocytes

Few (100-1000) reach the uterine tubes

97
Q

Blocks to Polyspermy

A

Cortical Reaction: Once bound to the oocyte membrane, the sperm fuses to it, allowing the contents of the sperm to enter the egg. Upon entry of a sperm (Not yet jointed DNA), Ca2+ surges from the ER of the oocyte, causing a cortical reaction
- Cortical granules release enzymes (Zonal Inhibiting Proteins/ZIPs)
- ZIPs destroy sperm receptors
- Spilled fluid binds water and swells, detaching other sperm

98
Q

Acrosomal Reaction

A

Sperm binds to the ZP3 molecules in the zona pellucida, causing a rise in Ca2+ levels in the sperm

This rise in Ca2+ triggers the acrosomal reaction: burrowing of sperm through the membrane surrounding an oocyte

Acrosomal Reaction: Acrosomal enzymes digest holes through the zona pellucida, clearing a path to the oocyte membrane

The sperm forms an acrosomal process, binding the sperm to the oocyte receptors

99
Q

Effects of Cortical Reaction on the Oocyte

A

Once the Ca2+ surge occurs in the secondary oocyte, it begins meiosis II, resulting in an ovum and second polar body

Once the ovum is present, the sperm and ovum nuclei swell and approach each other until a mitotic spindle forms between them

The chromosomes then intermix and fertilization is accomplished.

100
Q

Why does the secondary oocyte need to go through meiosis II?

A

After meiosis I, the primary oocyte has 46 chromosomes, if DNA combination occurred here, there would be too many chromosomes and the sperm DNA would not be able to combine

101
Q

Where does fertilization take place?

A

Primarily in the fallopian tube

102
Q

Growth of a zygote

A

Zygotes go through repeated MITOSIS

As it is growing, it is moving through the fallopian tube toward the uterus

After 3 days of growth, it becomes a Morula: a bunch of cells that form a ball. It has no differentiation and no “parts”

After 4 days, it becomes an early blastocyst: the ball hollows out, fills with fluid, and “hatches” from the zona pellucida

After 7 days, it becomes an implanting blastocyst: the hollow ball begins to differentiate

103
Q

Blastocyst Anatomy

A

Trophoblast Layer: A layer on the outer ring of the blastocyst that produces Human Chorionic Gonadotropin (HCG) which stimulates the growth of the corpus luteum as well as placenta formation

Zona Pellucida: The outer “shell” that degenerates after the blastocyst matures

104
Q

Implantation of the Blastocyst

A

Once in the grooves of the uterine wall, the blastocyst is covered by endometrial cells, protecting it and providing nutrients

Implantation is completed by day 12

105
Q

Hormones of Pregnancy

A

These hormones are secreted by the corpus luteum until the placenta takes over after involution

Estrogen: Increases 30x normal by the end of gestation, secreted by the corpus luteum and then the placenta, causes tissue growth in the fetus and mother

Progesterone: Secreted by the corpus luteum and then the placenta, suppresses FSH & LH as well as uterine contractions, prevents premature childbirth and menstruation

Human Chorionic Gonadotropin (HCG): Secreted by the blastocyst & the placenta, detectable in urine 8-9 days after conception, stimulates the growth of the corpus luteum

Human Chorionic Somatomammotropin

106
Q

Glands in Pregnancy

A

The pituitary gland grows about 50% larger during pregnancy, leading to an elevated level of thyrotropin, prolactin, & ACTH

The thyroid gland grows about 50% larger, increasing the metabolic rate of the mother and fetus

Parathyroid glands enlarge, increasing osteoclast activity to build the bones of the baby

Aldosterone secretion rises, increasing Na+ reabsorption, keeping it in the body to supply the baby

107
Q

Hormone Levels Throughout Pregnancy

A

For the first 4 weeks after ovulation, estradiol is produced with progesterone coming into play around week 2

Around week 4, HCG is released in great quantity, keeping the corpus luteum going with estradiol and progesterone secretion. Estradiol & Progesterone levels slowly rise for the next few weeks.

Once the corpus luteum goes through involution, HCG levels decrease drastically as the placenta takes over. Once the placenta has taken over, Estradiol & Progesterone levels rise greatly and HCG levels off but does not stop being produced.

Because the placenta has taken over, the corpus luteum dies off

108
Q

Digestive System Adjustments to Pregnancy

A

Morning Sickness: Nausea, especially when waking up, is thought to occur due to the rapidly rising hormone levels

Constipation & Heartburn: Potentially caused by reduced intestinal motility and pressure on the stomach causing reflux of gastric contents

109
Q

Metabolism Adjustments to Pregnancy

A

The pituitary gland increases in size & function causing the thyroid to increase in size and function. This increases metabolic function

Basal Metabolic Rate increases by about 15%

Appetite may be strongly stimulated

110
Q

Nutrition Adjustments to Pregnancy

A

The body is in demand of higher protein, iron, calcium, and phosphates

A pregnant woman needs extra iron to support hers and the baby’s oxygen & hemoglobin requirements

Vitamin K is given late in pregnancy and to newborns to promote prothrombin synthesis

Vitamin D supplements help calcium absorption which is required to build bones

Folic Acid supplementation reduces the risk of neurological fetal disorders

111
Q

Circulatory System Adjustments to Pregnancy

A

The mother’s blood volume rises about 30% during pregnancy (about 1 L more than normal)

This occurs due to fluid retention and hemopoiesis (supplying the baby with blood & nutrients)

Cardiac output rises 30-40% above normal by week 27 because the blood has to pump through the mother and baby

112
Q

Respiratory System Adjustments to Pregnancy

A

Tidal Volume & minute ventilation increase by about 40%. Deeper breaths mean more oxygen per breath to meet the increased demands

Oxygen requirements rise due to increased metabolic rate and the needs of the fetus

Low CO2 in the mother’s blood promotes CO2 diffusion from the fetus

Within the last month of the pregnancy, breathing will become easier due to pelvic expansion & the baby dropping lower

113
Q

Urinary System Adjustments to Pregnancy

A

Aldosterone increases to save Na+ for the baby

GFR increases by 50% and urine output is slightly elevated

The pregnant uterus compresses the bladder causing frequent urination

114
Q

Integumentary System Adjustments to Pregnancy

A

The skin grows to accommodate the expansion of the abdomen & breasts, resulting in stretch marks

Added fat deposition occurs in the hips & thighs

Melanocyte activity increases in some areas, resulting in darkening of the areolae

115
Q

Braxton Hicks Contractions

A

Relatively weak contractions of the uterus that strengthen late in pregnancy and cause false labor

Contractions transform suddenly into powerful labor contractions

116
Q

Progesterone in Uterine Contractions

A

Progesterone inhibits uterine contractions and levels start to decline after 6 months

Progesterone can sometimes be given in scenarios of early labor prevention

117
Q

Estradiol in Uterine Contractions

A

Estradiol stimulates uterine contractions and levels continue to rise throughout pregnancy

118
Q

Initiation of Labor

A

In the last few weeks of pregnancy, the fetus secretes cortisol, stimulating the placenta to secrete more estrogen

Estrogen induces oxytocin receptors on the uterus

Oxytocin from the fetus & the mother’s posterior pituitary stimulate the uterus to contract

Oxytocin also stimulates the placenta to make prostaglandins, which stimulate more vigorous contractions of the uterus as well as the production of more prostaglandins

The uterine contractions have a positive feedback relationship with the posterior pituitary, releasing more oxytocin and causing more contractions

119
Q

Positive Feedback Theory of Labor

A

Labor is induced by the stretching of the cervix

Cervical stretching stimulates oxytocin secretion

Oxytocin stimulates contractions of the uterus

Uterine contractions stimulate more cervical stretching

120
Q

Labor Pain

A

Muscles become deprived of blood due to the long periods of contraction. This causes a build-up of Lactic Acid

Stretching pain is caused by an unusually large head/brain of the infant or the narrow pelvic outlet

121
Q

Dilation Stage of Labor

A

Early Dilation: The cervix widens slowly over 6-12 hours while the uterus slowly increases contractions. The dilation of the cervix can give doctors an estimate of how close the mother is to birth

Late Dilation: The cervix is much wider, allowing for the baby to exit

122
Q

Expulsion Stage of Labor

A

This stage occurs from when the mother is at full dilation until the baby is born

Contractions occur every 2-3 minutes

The baby will be crowning: the head is sticking through

The umbilical cord is typically oriented on the top of the uterus

123
Q

Placental Stage of Labor

A

The placenta detaches, usually with a slight tug on the umbilical cord

Sometimes parts of the placenta will remain in the uterus, warranting a surgical operation to get those pieces out otherwise the placenta can become toxic

124
Q

Puerperium

A

The first 6 weeks postpartum

During this time, the mother’s anatomy & physiology stabilize, and reproductive organs return nearly to their pre-pregnancy state

Breastfeeding promotes the involution of the uterus

Breastfeeding suppresses estrogen secretion, making the uterus more flaccid

Breastfeeding also stimulates oxytocin secretion, which causes the myometrium to contract and firm up the uterus sooner

125
Q

A baby’s first breath

A

The baby will have central acidosis (High CO2 concentration) from not breathing. This will trigger the respiratory control centers to cause the first inspiration

The first breath is the hardest one will ever take because the airways are small and the lungs are collapsed

Surfactant in the alveolar fluid helps to reduce surface tension

Respiratory rate is typically 45 breaths per minute for the first two weeks then slowly declines (physiologically declines through chest-to-chest contact)

126
Q

Lactation

A

The synthesis & ejection of milk through the mammary glands

Breasts stimulated by a nursing infant or mechanical device will not stop producing milk

127
Q

Development of the Mammary Glands

A

High estrogen levels during pregnancy cause the ducts of the mammary glands to grow and branch

Progesterone stimulates the budding & development of acini at the ends of the ducts

128
Q

Colostrum

A

Similar to breast milk in protein and lactose, but contains 1/3 less fat

This is the sole nutrition source for the first 1-3 days after birth until milk is produced

It is cloudy & yellow

It contains IgA to protect the baby from gastroenteritis

129
Q

Breastfeeding effects on pregnancy

A

Breastfeeding suppresses hormone levels, keeping another fertilization/implantation from happening

This provides a natural means of spacing births

130
Q

Feedback Mechanism of Lactation

A

Mechanoreceptors in the nipples are stimulated by the suckling infant, sending afferent impulses to the hypothalamus

The hypothalamus sends efferent impulses to the posterior pituitary, causing a release of oxytocin

Oxytocin stimulates myoepithelial cells in the breasts to contract

Alveolar glands respond to these contractions by releasing milk through the ducts of the nipples

Milk being released causes the baby to continue suckling, further stimulating and completing the positive feedback loop

131
Q

Milk Production Feedback Mechanism

A

Mechanoreceptors in the nipples are stimulated by the suckling infant, sending afferent impulses to the hypothalamus

The afferent impulses inhibit hypothalamic neurons that release dopamine and cause the hypothalamus to release Prolactin Releasing Factors (PRF) into the portal circulation

The anterior pituitary secretes prolactin to the blood

Prolactin targets the lactiferous glands in the breasts

Lactiferous glands increase their milk production

132
Q

Prolactin Levels with Nursing

A

When the baby is first born, mothers feed it every 2 hours or so

The suckling of the baby causes prolactin to surge 10-20x the normal level for about an hour

By spreading out the time between feeding, prolactin spikes will also become less frequent and less intense

133
Q

Advantages of Breast Milk

A

Fats & Irons are easily absorbed

It contains beneficial chemicals (IgA, Complement proteins, Lysozyme, Interferons, & Lactoperoxidase) that build the non-learning immune system of the baby

Interleukins & prostaglandins prevent overzealous inflammatory responses (the baby will be less likely to have allergic reactions)

It has a natural laxative effect, helping to eliminate bile-rich meconium and prevent jaundice

It encourages bacterial colonization of the large intestine

134
Q

Female Birth Control

A

A pill that is taken, dosing the body with estrogen and progestin, inhibiting FSH & LH and preventing the ovarian follicle from maturing

The morning-after pill is a very high dose of estrogen and progestin that induces menstruation

Biol 233 (4 decks)

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