A&P Final Study Guide

testicles

testicles

produce male gamete and male sex hormones, two in number- inguinal canal, retained testes produce testosterone but no sperm bull will mate but usually will not settle a cow

monorchid

failure of one teste to descend

cryptorchid

failure of both testes to descend

scrotum

contains the testes, regulates the temperature of the testes for sperm production, spermatogenesis occurs at a temperature below core body temperature

tunica dartos muscle

smooth muscle layer lies beneath the scrotal skin, sensory neurons for temp, pushes the testes closer to the body for warmth and relaxes to cool, smooth muscle allows for sustained contractions

spermatic cord

regulates the temp of the testes for sperm production

cremaster muscle

located along the spermatic cord and attaches to the testes to regulate the temp, contraction aids in blood flow to the testes and increase/decrease cooling efficiency

pampiniform plexus

counter current heat exchange causes a cooling of arterial blood supply single artery surrounded by a network of veins (increased surface area)

convoluted testicular artery

surface of the testes to decrease blood temp

seminiferous tubules

functional unit of the testes and site of spermatogenesis, contain Sertoli cells to nurse developing spermatozoa, interstitial space has leydig cells to produce testoerone

describe where the sperm travels through

seminiferous tubules, rete testis, efferent ducts, epididymal duct, ductus deferens

epidiymis

duct located on outside of the testes composed of head body and tail

functions of epididymis

concentrate sperm, store sperm, transport sperm, site of sperm maturation (40-60 days)

ductus (vas) deferens

connects epidiymis to the urethra of the penis, transports sperm at the time of ejaculation, cut to sterilize male

what are the four male accessory sex glands

ampullae, seminal vesicles, prostate gland, bulbourethral (cowpers ) gland

ampullae

glandualar enlargement associated with the terminal parts of the ductus deferens, well developed in the stallion and bull and ram but not present in boar, adds volume to the ejaculate

seminal vesicles

paired glands that enter dorsocranial to the pelvic urethra, supply nutrients for the sperm following ejaculation and deposition into the female repro tract, include carbs (energy), ions (buffers), and enzymes that activate the sperm, contributes large portion of ejaculate volume in stallion and boar

prostate gland

lie sin close proximity to the bladder and pelvic urethra and considerable variation in size, some parts extend under the urethral muscle with multiple ducts opening into the urethra, produce alkaline substance gibing semen its characteristic odor, clean and lubricate the urethra ahead of the sperm to rupture and die

bulbourethral or cowpers gland

paired glands located on either side of the pelvic urethra near the ischial arch, most species are small and dense connective tissue except boar which is large, clean and lubricate the urethra, secretion is thick viscous and very slippery, boar produces gelatinous material that forms a coagulation plug in the female cervix

Penis proper

organ of copulation, muscular organ characterized especially by its spongy erectile tissue that fills with blood under considerable pressure during periods of sexual arousal

corpora cavernosa

erectile tissue that fills with blood

urethra

duct through penis that carries sperm and urine

fibroelastic penis type

contains dense collagenous tissue, firm when not erect (ruminant and swine)

musculocavernous penis

blood sinusoids predominate over connective tissue, flaccid when not erect (stallion)

retractor penis muscle

attached to the sacral vertebra, relaxes during sexual excitement

glans penis

terminal portion of penis

seminiferous tubules

sperm producing units of the testes, make up approx 90% of the testes mass, spermatogenesis occurs within the lumen of these long, highly coiled structures

sertoli cells

provide nourishment for the developing sperm located within the seminiferous tubules- contains androgen binding protein

leydig or interstitial cells

produce testosterone, located between the seminiferous tubules

spermatogenesis

several mitotic cell division (nonreductional division), two meiotic cell divisions (reductional) - chromosome number reduced to haploid, first and second division have two identical diploid cells, two contain Y chromosome and two contain X chromosome

sperm cell

head - contains genetic material (chromatin) and enzymes (in acrosome) necessary for fertilization, neck- attaches the head to the midpiece, midpiece- produces energy for the sperm, tail- propels sperm cell

Hormone process within male repro

hypothalamus produce gonadotropin releasing hormone (GnRH) which controls the release of two hormones from anterior pituitary called gonadotropin hormones (FSH and LH) which are released into the blood and go to the gonads where the stimulate specific functions

LH in male

stimulates the leydig cells to produce testosterone

testosterone functions

stimulates growth and development and secretory activity of accessory glands, stimulates growth of the repro tract at puberty, initiates spermatogenesis, necessary for sperm survival, responsible for secondary sex characteristics: male voice, muscle development, crest over the neck, libido, whiskers in man

FSH in male

stimulates the Sertoli cells to produce nutrients for the sperm

erection

neural response, stimulate of penis, visual or environmental stimulus (female in estrus), learned behavior (stallion walking to breeding area), requires vasodilation within penis (increased blood)

Ejaculation

prior: spermatozoa moved from epididymis- through vas deferens, into pelvic urethra, termed emission, in urethra mixed with accessory gland secretions and contractions around urethra to eject semen

what does the female repro tract consist of

2 ovaries, 2 uterine ducts (oviducts), uterus, vagina, vulva

external female genitalia

vulva and clitoris (homologous to male penis)

vagina

between external genitalia and cervix, site of semen deposition during natural service, urethra empties into the vagina, passageway for fetus at birth

cervix

lies between vagina and uterus, composed of connective tissues, seals uterus during pregnancy and protecting fetus from microorganisms, site of semen deposition for boars and stallion

uterus

site of placental attachment (13-37 days), nourishes the growing fetus, expels at parturition, composed of body and horns

oviduct

long convoluted tube connecting uterine horns to infundibulum, transport sperm to site of fertilization with muscle contractionsw

where is the site of fertilization in female

oviduct (ampulla-isthmus)

ovaries

paired, shape vary with species, produce ovum, produce female sex hormones (estrogen and progesterone)

oogonia

primitive gamete of the female, by birth will have the max number they will ever have, hormone stimulus initiates growth and development of a new follicle (result is acquisition of layers of cells)

primary follicle

surrounded by single layer of cells

secondary follicle

surrounded by double layer of cells

tertiary follicle

cells begin migration to one side leaving a cavity call antrum

where is estrogen produced

by cells lining the antrum

mature or Graafian follicle

ready to ovulate, follicle wall becomes thin, ovum still attached to follicle wall

ovulation

follicle ruptures and ovum released and caught by infundibulum, ovum oozes out

development of corpus luteum

after the ovum escapes from the mature follicle cells of the follicle are strucurally and biochemically transformed into a “yellow body” also called…, produces progesterone, if animal does not get pregnant this regresses and new follicle begins to develop after hormone, in absence of pregnancy this is destroyed by luteolysis which forms corpus albicans- remanent of previous

hormones identical to male system

GnRH, FSH -follicle stimulating hormone, LH- lutenizing hormone, FSH and LH are gonadotropin hormones that stimulate follicular growth both necessary, antrum of growing follicle develops and produces estrogen

functions of estrogen

excitatory hormone in female (induces heat), stimulates growth of cells of uterus and oviduct in preparation for conception and pregnancy, coordinates events associates with sperm and egg transport, initiates duct growth and development in the mammary tissue, lactation follows reproduction has secretory tissue and ducts and cisterns which estrogen stimulates, secondary sex characteristics like feminine traits and site of fat deposition

when the follicle is mature

a surge of LH is released this causes rupture of follicle, development of CL, and produce of progesterone

functions of progesterone

complete uterine growth initiated by estrogen and thus prepares uterus for nourishment of developing embryo if pregnancy occurs, support pregnancy by maintaining quiescent state of repro tract and suppresses mating behavior, prevents ovulation, stimulates growth and development of the secretory tissue in the mammary system

estrous cycle

series of events occurring from one heat period to the next beginning at puberty, adj

estrus

noun, refers to hear or the period of the time when the female is receptive to the male

why do females not cycle contunously

in wild offspring only survive if female had plenty of food so duration of gestation and food available is closely associated to initiation of estrous cyclicity

monestrous

one estrous period per year, fox and dog has two but still classifies

polyestrous

many estrous periods per year, cow and sow

seasonally polyestrous

many estrous periods during certain periods of the year, mare increasing daylight hours will have irregular in Jan and begin again by April, ewe decreasing daylight hours and begin cycling in August up north and later as further south,

anestrous

period of time when animal is NOT cycling

behavioral signs of estrus

standing to mounted, mounting other animals, social behavior- restless gregarious and vocal, frequent urination, mucous discharge

fertilizaton

union of male and female gametes

what are the stages of development

2 cell, 4 cell, 8 cell, morula, blastocyst, embryo, and fetus

embryo

developing organs similiar appear across all livestock (less than day 45 in cattle)

fetus

organs defined species different (great than day 45 in cattle)

attachment of placenta to endometrium

chorionic amniotic and allantoic membranes develop around the new embryo and the chorion attaches to the uterus and embryo gets nutrients/discharge wastes through these, attachment begins vary, placenta attached to uterus and provides nutrients and waste exchange, diffuse and cotyldonary placenta type

placental attachment begins when in livestock

22 days in cows, 15 days in ewes, 13 days in sows, 37 days in mares

palpation

deep structures of the body are felt by the hands of the observer, takes time and lots of practice

ultrasound

dense/hard tissues reflect echoes and appear bright white (bone), soft tissues and fluid do not reflect echoes (anechoic) and appear black

genital tubercle

body of tissue during development of the penis or vulva, during fetal development location of genital tubercle allow for gender determination

male gender determination

genital tubercle migrates toward the umbilical cord or see scrotum between the rear legs

female gender determination

gential tubercle migrates towards the tail or see teats btwn rear legs

embryonic pregnancy loss

fertilization through organ development (day 0-45)

fetal pregnancy loss

completion of organ development (day 45-birth)

natal pregnancy loss

at birth

neonatal pregnancy loss

birth to 4 weeks of age

developmental programming of offspring

exposure during a critical period in development may influence later production life of the animal, embryonic to fetal is critcal

if during pregnancy the dam is exposed to poor nutrition, heat stress, and transportation stress then what may the offspring experience

increased sickness during neonatal period, decreased postnatal growth rates, female offspring show greater pregnancy loss, male offspring have lower carcass yield and quality

parturition

termination of gestation, controlled by hormones produced by fetus and dam, initiated by fetus, cervix dilates and pelvic ligaments relax, uterine muscles contract and generate pressure, fetuses of cow and mare and ewe assume positions in which the front feet are extended with the head between them, fetal pigs do not orient themselves in any one direction

dystocia

abnormal or difficult labor

factors associated with distocia

heavy birth weight of calf is major cause in cattle, weight of calf in relation to pelvic size is very important, age of cow plays a role due to difference in size of pelvic opening, heifers have a greater incidence of calving problems, present rump first or head or leg folded back

factors affection repro performance

nutrition, environment - temp humidity and seasonality, anatomical defects in repro tract, endocrine system imbalance, diseases- brucellosi, metritis, vibriosis, leptiospirosis, trichomoniasis, IBR

necessary components of female repro

willing and able to accept the male near a time when the egg (ovum) is released from the ovary (ovulation)

necessary components of male repro

must be will and able to service female and deliver spermatozoa to proper site in female repro tract at a proper time for conception to occur

conception

mating or union of male and female gametes

what are the two distinct anatomical and functional differences between the male and female repro systems

male - develop gametes is continuous process with infinite number sperm

female- finite number of gametes and is cyclic process