Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Chapter 17 (Human Reproduction) > Flashcards

Chapter 17 (Human Reproduction) Flashcards

1
Q

Organs of the Male Reproductive System

A
  • testes, suspended outside abdominal tract in skin-covered sac called the scrotum
  • seminal vesicles
  • prostate gland
  • bulbourethral gland
  • penis
  • epidiymis
  • vas deferns
  • ejaculatory duct
  • urethra
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Testes

A
  • descent is usually complete by a the seventh month of gestation
  • location of the scrotum provides a cooler environment essential for spermatogenesis
  • produces sperm within the seminiferous tubules
  • secretes testosterone in interstitial (leydig) cells that lie in the connective tissue between the seminiferous tubules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Spermatogenesis

A
  • process where undifferentiated diploid cells (spermatogonia) are converted into haploid spermatozoa (sperm)

3 major steps

  1. mitotic proliferation
    - sperm-forming daughter cells divides mitotically twice more to form four identical primary spermatocytes
  2. meiosis
    - each primary spermatocyte forms two secondary spermatocytes. after the second meiotic division, there are four spermatids
    - 16 spermatozoa result from each spermatogonium that goes through the process
  3. packaging
    - spermiogenesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Spermatozoa

A
  • remains closely associated with sertoli (nurse) cells throughout development

4 parts

  1. head
    - contains the nucleus/dna
  2. Acrosome
    - enzyme filled vesicle that caps tip of the ehad
    - used to penetrate the ovum
    - formed by endoplasmic reticulum and golgi complex before the organelles are discarded
  3. Midpiece
    - mitochondria are concentrated here
  4. Tail
    - provides mobility for spermatozoa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Semen

A
  • average volume 2.75 ml
  • ranges from 2-6 ml, typically higher volumes following periods of abstinence

sperm count:

  • average ejaculation contains 180 million sperm (66 million/ml)
  • can have up to 400 million
  • males with less than 20 million /ml are considered infertile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sertoli Cells

A
  • forms blood-testes barrier
  • provides noursihemnt
  • phagocytic funciton
  • secretes seminiferous tubule fluid which flushes released sperm from the tubules into the epididymis for storage and additional processing
  • secretes androgen-binding protein
  • site of action to control spermatogenesis: releases inhibin and acts in negative-feedback fashion to regulated FSH secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Epididymis

A
  • stores and concentrates sperm

- increases sperm motility and fertility prior to ejaculation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Seminal Vesicles

A
  • supplies fructose for energy
  • supplies prostaglandins which promote smooth muscle motility in both male and female reproductive tracts
  • provies more than half the semen
  • secretes fibrinogens (makes sperm clot)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Prostate Gland

A
  • contributes alkaline fluid that neutralizes acidic vaginal secretions
  • provides clotting enzymes and fibrinolysin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Bulbourethral Galnd

A
  • releases lubricating mucosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sexual Response Cycle

A
  1. Excitement phase
    - erection and heightened sexual awareness
  2. Plateau phase
    - steadily increasing heart rate, blood pressure, respiratory rate and muscle tension
  3. Orgasmic phase
    - ejaculation and other responses that are collectively experienced as intense physical pleasure and heightened emotions
  4. Resolution phase
    - return of genitalia and body systems to pre arousal state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Female Responses to Sexual Cycle

A
  1. Excitement
    - swelling of labia and erection of clitoris due to parasympathetically induced vasocongestion
    - nipples and breasts enlarge i size
    - release of mucus (bartholin’s gland) causes lubrication
  2. plateau
    - uterus raises upward, lifting the cervix and enlarging the upper 2/3 of the vagina. creates space for ejaculation to be deposited
    - physical relaxation
  3. orgasm
    - contraction occurs most intensely in the engorged lower third of the vagina
    - females can experience 12 successive orgasms
  4. resolution
    - pelvic vasocongestion and systemic manifestation gradually subside
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ovaries

A
  • primary female reproductive organs
  • produce ova (oogenesis)
  • secretes female sex hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Estrogen

A
  • essential for ova maturation and release
  • establishment of female secondary sexual characteristics
  • essential for transport of sperm from vagina to fertilization site in the oviduct
  • contribution to breast development in anticipation of lactation
  • promotes the growth of the myometrium
  • development of mammary ducts within the breasts
  • enlargement of external genitalia

during pregancy:
- fetal adrenal cortex produces DHEA, which is converted into estrogen, until the placenta develops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Progesterone

A
  • promotes the growth and maintenance of the endometrium
  • suppresses the uterine contractions to prevent miscarriage
  • promotes the mucus plug formation in the cervix
  • contributes to breasts’ ability to produce milk
  • ## converts the endometrium into a highly vascularized, glycogen-filled tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Oogenesis

A
  • takes 12-50 years to complete on a cyclic basis from onset of puberty until menopause
  • female has a limited supply of germ cells
  • each primary oocyte yields only one cytoplasm rich ovum and 3 cytoplasm poor polar bodies
17
Q

Oogonia

A
  • undifferentiated primordial germ cells in fetal ovaries
  • divide mitotically and give rise to 6-7 million oogonia by the 5th month of gestation
  • during the last part of fetal life, the first meiotic division occurs
  • now known as primary oocytes (diploid)
  • can remain in meiotic arrest for years until they are prepared for ovulation
18
Q

Primary Oocyte

A
  • surrounded by a single layer of granulosa cells

- oocyte + granulosa cells = primary follicle

19
Q

Primary Follicle

A
  • after development starts there are two possible fates
  • reach maturity and ovulate
  • degenerate to form scare tissue (atresia)
  • between puberty and menopause, follicles develop into secondary (antral) follicles on a cyclic basis
20
Q

Ovarian Cycle

A
  1. follicular phase
    - dominated by presence of maturing follicles
  2. luteal phase
    - characterized by the presence of the corpus luteum
21
Q

Follicular Phase

A
  • first half of the cycle
  • granulosa cells of primary follicles proliferate
  • oocyte inside each follicle enlarges
  • Theca cells in follicles secrete an increased amount of estrogen
  • rapid follicular growth continues throughout the phase
  • one follicle grows more rapidly and matures about 14 days after onset. follicle ruptures to release oocyte from ovary - ovulation
22
Q

Luteal Phase

A
  • last 14 days of ovarian cycle
  • old follicular cells undergo structural transformation to form a corpus luteum
  • becomes highly vascularized
  • becomes fully functional within 4 days after ovulation
  • continues to increase in size for another 4-5 days
  • if released ovum is not fertilized and does not implant, the corpus luteum degenerates about 14 days after formation
23
Q

Hormonal Interactions

A

Follicular Phase

  • rise in FSH signals ovarian follicle to secrete more estrogen
  • rise in estrogen feeds back to inhibit FSH secretion. it declines as the phase progresses
  • LH rises and peaks mid-cycle during ovulation

Luteal Phase

  • estrogen output decreases and the follicle is converted into a corpus luteum
  • corpus luteum secretes progesterone and estrogen
  • progesterone output inhibits release of FSH and LH
  • low LH - corpus luteum degenerates
  • progesterone levels decline, FSH can start to rise again, initiating a new cycle
24
Q

Uterine Cycle

A
  1. Menstrual Phase
  2. Proliferative Phase
  3. Secretory or Progestational Phase
25
Q

Menstrual Phase

A
  • characterized by the discharge of blood and endometrial debris from the vagina
  • first day of menstruation is considered start of new cycle
  • coincides with the end of ovarian luteal phase and the onset of the follicular phase
  • release of uterine prostaglandin which: causes the vasoconstriction of endometrial vessels, disrupts blood supply, causes death of endometrium, stimulates mild rhythmic contractions of the uterine myometrium to help expel blood and endometrial debris
26
Q

Proliferative Phase (LH Surge)

A
  • begins concurrent with last portion of ovarian follicular phase
  • endometrium starts to repair itself and proliferate under the influence of estrogen and newly growing follicles
  • estrogen dominant proliferative phase lasts from end of menstruation to ovulation
  • peak estrogen levels trigger LH surge responsible for ovulation
27
Q

Secretory / Progestational Phase

A
  • uterus enters this phase after ovulation when a new corpus luteum is formed
  • corpus luteum secretes a large amount of progesterone and estrogen
  • endometrial glands actively secrete glycogen
  • if fertilization and implantation does not occur: the corpus luteum degenerates and a new follicular phase and menstrual phase begins once again
28
Q

Fertilization

A
  • oviduct/fallopian tube is site of fertilization. normally in upper third of oviduct (ampulla)
  • must occur within 24 hours of ovulation
  • sperm can usually survive about 48 hours but can survive up to 5 days
  • factors that assure successful transport of the sperm to the egg
    1. contractions of the myometrium
    2. upward contractions of oviduct smooth muscles
    3. allurin released by mature eggs
  • once sperm reaches the ovum, a chemical change occurs that makes the outer layer impermeable to any more sperm
  • plasma membrane of sperm produces protein fertilin (olfactory receptor hRO17-4) that binds to ovums cell membrane protein ZP3, causing a fusion
  • hRO17-4 responds to smell of ovum
29
Q

Implantation

A
  • fertilized ovum divides mitotically until it becomes a blastocyst that is capable of implantation
  • blastocyst implants in the endometrial lining using enzymes released by trophoblasts
  • the enzymes carve a hole in the endometrium for implantation, and they release nutrients from endometrial cells to be used by the developing embryo
30
Q

Placenta

A
  • develops after implantation
  • organ of exchange between maternal and fetal blood
  • acts as transient, complex endocrine organ that secretes pregnancy hormones
    1. human chorionic gonadotropin
  • maintains the corpus luteum until the placenta takes over function in the last two trimesters
    2. estrogen
  • essential for maintaining normal pregnancy
    3. progesterone
  • essential for maintaining normal pregnancy
31
Q

Gestation

A

physical changes:

  • uterine enlargement
  • breasts enlarge and develop ability to produce milk
  • volume of blood increases 30%
  • weight gain
  • respiratory activity increases about 20%
  • urinary output increases
  • kidneys excrete additional wastes from fetus
  • nutritional requirements increase
32
Q

Partuition

A
  • labour, delivery, birth
    requires:
  • dilation of the cervical canal
  • contraction of uterine myometrium

changes before parturition

  • uterus remains quiet and inactive during the first two trimesters
  • high progesterone levels exert inhibitory effects on uterine muscles
  • in the third trimester, the uterus becomes more excitable to initiate mild contractions “braxton hicks”
  • closed cervix keeps the uterus sealed
  • initiation of parturition and the hormone relaxin causes the cervix to soften
33
Q

Relaxin

A
  • relaxin is produced by the corpus luteum and placenta

- relaxin relaxes the pelvic ligaments for parturition

34
Q

Prostaglandin

A
  • promotes cervical enzyme production

- these enzymes degrade collagen fibers which help to soften the cervix

35
Q

Oxytocin

A
  • hypothalamus synthesizes
  • posterior pituitary stores it
  • travels through the blood

causes

  1. powerful uterine muscles contractions
  2. increases uterine responsiveness x100
  3. increased oxytocin receptors in the myometrium for a strong endometrial contraction (critical threshold)
36
Q

Corticotropin Releasing Hormone

A
  • fetal placenta creates CRH
  • CRH determines the onset of labor, and promotes fetal lung maturation
  • stimulates the pituitary gland to secrete ACTH which increases the amount of cortisol and DHEA
  • cortisol stimulates the synthesis of pulmonary surfactant. increases lung expansion and reduces the work of breathing
37
Q

Stages of Labor

A
  1. Cervical dilation
    - longest stage, cervix can dilate to 10-12cm
  2. Delivery of the baby
    - lasts 30-90 minutes
  3. Delivery of the placenta
    - shortest stage, 15-30 minutes
38
Q

Lactation

A

Prolactin:

  • stimulates the synthesis of enzymes essential for milk production by alveolar epithelial cells
  • withdrawal of placental steroids at parturition initiates lactation. sustained by suckling
  • triggers release of oxytocin and prolactin

Oxytocin:
- causes milk ejection by stimulating cells surrounding alveoli to squeeze secreted milk out through ducts

Physiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions