A&P II

Exam #3

purpose of meiosis

produce haploid gametes for sexual reproduction

haploid cells

23 chromosomes (1 set)

diploid cells

46 chromosomes (2 sets)

crossing over occurs in

between homologous chromosomes

independent assortment

random distribution of homologous chromosomes during meiosis

spermatogenesis occurs in

seminiferous tubules

primary spermatocyte

diploid cell that undergoes meiosis

sertoli cells

support sperm development + form blood-testis barrier

acrosomal reaction is triggered by

ZP3 binding on zona pellucida

polyspermy is prevented by

cortical reaction

meiosis II

haploid cells with single chromatids

increases genetic variation

crossing over + independent assortment

GnRH released from

hypothalamus

FSH

stimulates follicle development

LH surge causes

ovulation

hormone highest in follicular phase

estrogen

corpus luteum secretes

progesterone

hCG

Maintains corpus luteum

Secretory phase function

Prepares endometrium for implantation

causes menstruation

Drop in progesterone

Estrogen feedback effect

Negative + positive feedback depending on level

Proliferative phase hormone

estrogen

fertilization occurs in

fallopian tube

capacitation

Activation of sperm for fertilization

ZP3

Triggers sperm binding/acrosomal reaction

polyspermy

More than one sperm entering egg

zygote

Fertilized egg

blastocyst

Inner cell mass + trophoblast

inner cell mass becomes

embryo

produces hCG

trophoblast

gastrulation

Formation of 3 germ layers

amnion

Cushions/protects embryo in fluid

Ectoderm becomes

Nervous system + skin

Mesoderm becomes

Muscle, bone, cardiovascular system

Endoderm becomes

GI + respiratory lining

relaxin

Hormone that softens pelvic ligaments

Function of placenta

Gas, nutrient, and waste exchange

oxytocin

Stimulates uterine contractions

Stage 1 of labor

dilation

Stage 2 of labor

Expulsion of baby

Stage 3 of labor

placenta delivery

Homozygous

Same alleles

Heterozygous

Different alleles

Codominance ex.

AB blood type

Polygenic inheritance

Trait controlled by multiple genes

Phenocopy

Environmental mimic of genetic trait

senescence

aging of body systems

osteopenia

bone mass loss

atherosclerosis

Plaque buildup in arteries

telomeres

shorten with age

progeria

accelerated aging disease

LH surge cause

ovulation

hCG prevents

Corpus luteum breakdown

Estrogen does what feedback switch

Negative → positive feedback

Cortical reaction prevents

Polyspermy

Germ layers form during

gastrulation

vaginal mucosa

stratified squamous epithelium with rugae (ridges)

vaginal muscularis

smooth muscle

vaginal adventitia

fibroelastic connective tissue

Adults

vaginal pH is decreased (acidic) 

Adolescents

vaginal pH is increased

Amnion

forms sac with embryo, & protects from physical trauma

Chorion

helps form placenta & encloses embryonic body

Yolk sac

source of germ cells that migrate into the embryo to seed the gonads.

Primordial follicle

single layer of follicle cells surrounding oocyte

Primary follicle

two or more layers of granulosa cells

Secondary follicle

fluid-filled spaces within granulosa that merge to form vesicular follicle

pedigree charts

trace a particular genetic trait through several generations; helps to predict the future

Endometrium

mucosal lining of columnar epithelium

2 Layers: 

1. Stratum functionalis

2. Stratum basalis

Myometrium

muscular middle layer: interlaced bundles of smooth muscle

Perimetrium

outer covering of visceral peritoneum

Infundibulum

open funnel-shaped structure with finger-like projections (fimbriae) that drape over ovary

Ampulla

widened region arching over ovary

Isthmus

narrowed region where tube enters upper region of uterus

Rosacea

dilated blood vessel patches