a & p 2 sexual reproduction

sexual reproduction

offspring gets genetic material from two different parents

gametes

specialized cells that can combine genes to form new individuals

sperm

what is the male gamete?

ovum

what is the female gamete?

haploid

an organism or cell having only one complete set of chromosomes.

primary sex organs

gonads, used to produce gametes

testes

what is the male primary sex organ?

ovaries

what is the female primary sex organ?

secondary sex organs

used to combine and nurture gametes

penis, prostate gland, seminal vesicles, ductus deferens, epididymis

what are the male secondary sex organs?

uterus, uterine tubes, vagina

what are the female secondary sex organs?

to store and move sperm

what is the purpose of the male secondary sex organs?

to move ovum and nurture embryo

what is the purpose of the female secondary sex organs?

secondary sex characteristics

external features that appear at puberty

pubic, axillary, and facial hair distribution, deeper voice, muscular build

what are the male secondary sex characteristics?

pubic hair, breasts, higher voices, wider pelvis

what are the female secondary sex characteristics?

sex determination

the biological mechanism that determines whether an organism will develop as a male or female

chromosomes

long sequences of DNA that contain genes

X and Y

what are the sex chromosomes?

male or female

what does the combination of sex chromosomes determine?

female default value

The concept that all human embryos begin with the same undifferentiated structures, and in the absence of a Y chromosome and SRY gene, they develop along the female pathway

female structures develop

what happens if no Y chromosome develops?

female structures degenerate + male structures develop

what happens if a Y chromosome develops?

XY

male sex chromosomes

XX

female sex chromosomes

sex determining region of the Y chromosome

SRY

SRY

makes TDF and triggers testes formation

testes determining factor

TDF

TDF

leads to preservation of male structures and secretion of anti-mullerian hormone

anti-mullerian hormone

a peptide secreted by the fetal testes that inhibits the development of uterus, uterine tubes, parts of vagina (degeneration of female structures)

morphologically female

what happens if TDF is absent or non-functional?

morphologically

refers to appearance

near the kidney

where do the testes develop?

7th week

around what week of development do testes begin to form?

inguinal canal into scrotum

what do the testes descend through?

around birth

when should the descent of testes be completed?

to keep them cool

why are testes kept outside the body cavity?

2

how many degrees below body temp should the testes be?

cryptorchidism

testes fail to descend

female designation, sterility

what can cryptorchidism lead to?

trisomy

3 copies of a chromosome, usually "embryonic lethal"

trisomy 21

leads to down syndrome

trisomy 18

edward's syndrome; causes low birth weight, heart defects, fatal by first year, though some live into 20s or 30s with significant mental handicaps

trisomy 13

causes severe organ and skeletal developmental issues, leads to a miscarriage, or is fatal within the first few days to a year

klinefelter syndrome

extra X chromosome; XXY or can even be XXXY

turner's syndrome

having only a single X chromosome; XO

atypical division during fetal development

what does turner's syndrome come from?

small/undescended testes, decreased testosterone + sperm production

what are the effects of klinefelter syndrome?

1:15000

what is the occurance of klinefelter syndrome?

low estrogen levels, secondary sex characteristics are not fully developed at puberty

what are some effects of turner's syndrome?

congenital adrenal hyperplasia

excessive cell growth in the adrenal glands

cortisol, aldosterone, androgens

what do the adrenal glands produce?

spermatozoa

a mature sperm cell

sustentacular (nurse) cells

- form blood-testes barrier

- support sperm development

- secrete fluids

epididymis

stores sperm and allows them to mature

seminiferous tubules

site of sperm production

follicle-stimulating hormone (FSH)

formed in the anterior pituitary and stimulates sperm production and follicles of ovary

inhibin

from nurse cells and inhibit sperm production

ductus deferens

carries sperm from epididymis to urethra

seminal vesicles

- 40% of the final volume

- slightly alkaline to buffer the acidic female reproductive tract

- uses fructose for energy

- activate flagella

prostaglandins

signaling molecules

signaling

what is the overall function of prostaglandin?

prostate gland

30% of volume and are clotting proteins with unknown function

bulbourethral gland

- secretions occur just prior to ejaculation

- alkaline to neutralize pH of male urethra

- provides some lubrication for intercourse

parasympathetic response

what type of response is erection?

sympathetic response

what type of response is emission?

emission

what happens when the bulbourethral gland secretions are released so that seminal fluid moves into the male urethra?

sympathetic

what type of response is ejaculation

ejaculation

-contractions of the bulbourethral muscle that surround the corpus spongiosum and contractions of ischiocavernosus muscle that surround the corpora cavernosa cause this

hormones from hypothalamus, anterior pituitary, and ovaries

what is the menstrual cycle controlled by?

28 days

around how long does the menstrual cycle take?

ovarian and uterine

what are the two main phases of the menstrual cycle?

pre-ovulatory (follicular) phase and post-ovulatory (luteal) phase

what are the 2 phases of the ovarian cycle?

follicular phase

The first phase of the ovarian cycle, during which a follicle (an oocyte and its surroudning cells) enlarges and matures and typically lasts from day 1 to day 14 of the menstrual cycle. The follicle secretes estrogen during this time period.

follicular-stimulating hormone

what hormone controls the follicular phase of the ovarian cycle?

1 year

how long does follicular development take?

luteal phase

corpus luteum secretes progesterone, which maintains endometrium and inhibits GnRH pulse frequency, which therefore inhibits FSH and LH

corpus luteum

what controls the luteal phase of the ovarian cycle?

luteinizing hormone (LH)

secreted by the pituitary gland to promote ovulation

progesterone

hormone that maintains the endometrium

GnRH pulse frequency

Changes in GnRH pulse frequency:

are controlled by estrogens and progestins

increase

estrogens ___________ pulse frequency

decrease

progestins ___________ pulse frequency

tipping point

when estrogen levels are high enough to cause a positive feedback loop instead of a negative feedback loop

proliferative phase and secretory phase

what are the two phases of the uterine cycle?

proliferative phase

- prepares the endometrium for implantation

- begins ~7 days after menses

- rising estrogen levels

- functional zone of the endometrium. thickens, secretes mucus, and increases vascularization

menses

menstrual cycle

secretory phase

endometrium secretes more mucus, which is maintained by progesterone from the corpus luteum

implantation of blastocyst

- corpus luteum is maintained

- progesterone levels stay elevated

- endometrium is maintained

no implantation of blastocyst

- corpus luteum degenerates after around 14 days

- progesterone is shut off

- endometrium is shed (menses begins)

erection

increased blood flow to the clitoris and greater vestibular gland

parasympathetic system

what system controls secretion of vestibule glands female?

secretion of vestibule glands

- provides lubrication for intercourse

- female secretion

climax

rhythmic contractions of smooth muscle around uterus and vagina

sympathetic system

what system controls the climax (female)

conception

needs to occur within 12-24 hours after fertilation

acrosomal enzymes

- kills and breaks apart granulosa cells

- dissolves zona pellucida

polyspermy

fertilization by more than one sperm

fast block

Na+ causes hardening of zona pellucida to prevent polyspermy

slow block

Ca2+ causes the removal of sperm receptors