ANFS240 Exam 4- reproductive & neuro

Testicle

Testicle

• site of spermatogenesis where sperm are created from stem cells

• Endocrine function, create and release hormones like testosterone

• Ovoid/ellipsoidal shape

• Smooth outer surface with a firm parenchyma

• Orientation and size varies based on species

Epididymis

• Adjacent to testicle

• Where maturation of sperm occurs

• 3 parts

  • Head- (blue) where sperm enter from testicle

  • Body (orange)

  • Tail- (pink) sperm exit here matured

Deferent Duct

• (Red) Continuous with tail of epididymis

• Long, thin tube that extends to urethra

Tunica vaginalis

• Membrane surrounding and enclosing testes

• Invagination and extension of peritoneum

• Both parietal and visceral layers

  • Visceral layer- tightly adhered to surface of testicle and epididymis

  • Space continuous with peritoneal cavity

  • Descend through vaginal ring-(blue) can cause inguinal hernia

Tunica albuginea (testicle)

• White covering that surrounds testicle, not epididymis

• Mediastinum- projection that extends into testicle and divides into halves

Spermatic cord

• varies in shape and length based on orientation of testes

• Includes

  • Pampiniform plexus

    • Spermatic vein

  • Spermatic artery

  • Deferent duct

  • Cremaster muscle

Cremaster muscle

• Muscle within spermatic cord that brings testes closer to body (retracting testicles)

• Contracts due to pain, temperature, fear

Scrotum

• Houses testicles, epididymis, spermatic cord

• Adhered to tough musculofibrous layer- tunica dartos

• External median groove called septum which divides left and right compartments

Male Urethra

• extends from bladder to most distal end of penis

• Carry both sperm and urine

• Can be divided into spongy (external) and pelvic (internal)

• Pelvic is where deferent ducts join

• Spongy exists within the penis and is surrounded by vasculature

Accessory reproductive glands

• Create and secrete fluid that sperm exists in during ejaculation

• Feeds and keeps sperm alive

• Increases amount of area sperm can be dispersed

• 4

  • Ampullae

  • Vesicular glands

  • Prostate

  • Bulbourethral glands

Ampullary glands

• (Blue) Enlarged portion of deferent duct

• Near or on top of bladder

• Shares duct with vesicular gland that allows both glands to secrete fluid into deferent duct

• Not found in boars or tomcats

Vesicular glands

• (Orange) Lateral to deferent ducts, shares duct with ampullae

• Vary in appearance based on species

  • Horses: large, smooth, bladder-like

  • Other domestics: bumpy, thick walled

• Not present in dog or cat

Prostate gland

• (Light blue) 1 gland with 2 parts

  • One part is spread through a portion of urethra wall

  • Second part is external to urethra, surrounds from outside

• Some species have both parts (dog/cat) and some only have one

• Very well developed in dog and cat

Bulbourethral glands

• (Pink) Paired, dorsal to urethra

• Most distal of accessory repro glands

• Not present in dog, very small in cat

Penis/Prepuce

• Suspended below trunk in all species except cat (circle is os penis)

• Prepuce/sheath covers free end of penis when not sexually aroused

  • 2 layers of prepuce

    • External(lamina externa): continuous with external integument

    • Internal(lamina interna): faces free end of penis, reflects back on itself in preputial cavity

Musculocavernous penis

• erection occurs secondary to engorgement of erectile tissue with blood

• Diameter and length increase with erection

• Much less connective tissue to allow for blood

Fibroelastic penis

• tough fibroelastic tissue, less open space

• penis is firm when not erect

• Does not increase much in diameter

• Lengthening of penis via sigmoid flexure

Os penis

• bone disconnected from skeleton

• feline and canine penis

• dorsal to urethra, within penile tissue for additional support and rigidity

Parts of penis

• Root- area of attachment, proximal

• Body- main part of penis

• Glans- distal part of penis

Corpus spongiosum

• (Orange) erectile tissue directly enclosing urethra

• allows urethra to remain patent when tissue is engorged

• forms bulb and glans of penis

Corpus cavernosum

• (Blue) paired erectile tissue that comprises bulk of the body of the penis

• tapers off at glans

Tunica albuginea (penis)

• (Pink) tough outer casing that surrounds corpus cavernosum

Retractor penis muscle

• retracts penis back into abdomen or prepuce (11)

Urethral process

• extension of urethra beyond glans

Penis comparative anatomy

Ovaries

• (Blue) Paired female gonads where gametes are produced

• endocrine function, where sex hormones are produced and released

• typically in dorsal and caudal half of abdomen

• surrounded by tunica albuginea

Ovarian cortex

• Outer layer of ovary

• structures at different stages and levels of development

Ovarian medulla

• Central layer of ovary (outlined in orange)

• Mainly blood vessels, nerves, tissue, etc

Follicle

• thin-walled fluid filled structure that contains oocyte

• expand in size as mature

• Ovulation- release of oocyte

Corpus Luteum

• tissue that forms where follicle ruptured (blue)

• “yellow body”

• secretes hormones that are required to maintain early pregnancy

Corpus Albicans

• Scar tissue remnant of CL (purple)

• “white body”

Oviduct

• Uterine tubes (green)

• Carry ovulated oocyte to uterus

• where fertilization occurs

Infundibulum

• Funnel/ “catcher’s mitt” (blue)

• Part of uterine tube closest to ovary

• Very thin walled with fingerlike projections called fimbriae

  • come into contact with ovary to collect ovum

Ampulla

• proximal segment closer to infundibulum (pink)

• larger in diameter than isthmus

Isthmus

• segment that follows ampulla (yellow)

• Part of uterine tube that connects to uterine horn

• Longer, thinner, convoluted (twisted)

Uterus

• enlarged portion of repro tract where fetus attaches and grows

• Most variation between species

• Two parts- uterine horns and uterine body

Layers of uterus

• Perimetrium- serosal outer layer

• Myometrium- muscular middle layer

• Endometrium- inner mucosal layer, very glandular

Uterine horns

• (4) shorter horns in species with 1 or 2 babies

• Very prominent horns in litter bearing species

Uterus comparative anatomy

Cervix

• sphincter that acts as a barrier, physical and chemical (pink)

• Fibrous elastic tissue and muscle

• Responsive to hormones that fluctuate through estrous cycle

• Pelvic cavity

Cervix comparative anatomy

• Cow/ewe/doe- firm, fibrous, several rings

  • Fornix formed by vaginal part of cervix bulging out into vagina

• Mare/bitch/queen- simple muscular cervix with vagina part and fornix

  • No annular rings

• Sow- very long and complicated, mucosal projections that come together to close lumen

  • No fornix, hard to tell where vagina begins and cervix ends

Vagina

• (10) Distal to cervix

• Thinner walls

• Less muscular and glandular

Vestibule

• (11) shared repro and urinary space

• somewhere in between cloaca and human tracts

• urethral opening and vaginal opening

Vestibule comparative anatomy

Vulva

• external portion of repro tract

• two vertically oriented labia meet at dorsal and ventral commissures

• In most species dorsal commissure is rounded and ventral is pointed

  • Inverse in mare

Clitoris

• analogous to male penis (14)

• Consists of 2 crura, a body, and a glans

  • only glans visible externally

• Found within ventral commissure of vulva

Broad ligament

• Suspensory apparatus for entire female repro tract

• Fold of peritoneum from dorsal body wall

• 3 parts

Mesovarium

• (6) Connects ovaries to body wall

Mesosalpinx

• (7) connects oviducts to body wall

Mesometrium

• (8) connects uterine horns and body to the body wall

Proper ligament of ovary

• strong cord of fibromuscular tissue (9)

• connects ovary to uterine horn

Intercornual ligament

• connects uterine horns to one another (5)

• dorsal and ventral ligaments

• important in diagnosis pregnancy in bovine (allows for manipulation of uterus)

Placenta

• Facilitates waste and nutrient exchange

• Hormone production for maintaining pregnancy

• No direct exposure of fetal/maternal blood

Fetal membranes

• form around embryo to protect

• transfer of nutrients and waste

  • Amnion

  • Allantois

  • Chorion

Amniotic membrane

• Innermost membrane (1)

• Surrounds amniotic cavity

  • Fluid that directly surrounds fetus

  • “clean”

  • Shock absorber

  • fetal development

• Thin, clear/white

Allantoic membrane

• Middle membrane (4)

• surrounds allantoic cavity

  • Dirty cavity

• Communicates with urachus

  • carries waste away

• Fused with chorion

Chorionic membrane

• Most external membrane (4)

• Fused to allantois

  • Chorioallantois

• Communicates with endometrium

Placental attachment

• not a smooth interface

• Villi on both surfaces

• Chorionic villi- extend from chorioallantois

• Endometrial villi- extend from maternal endometrium

Epitheliochorial placentation

• Least invasive, 6 layers

• Fetal layers

  • Fetal endothelium

  • fetal connective tissue

  • chorionic epithelium

• Maternal Layers

  • maternal epithelium

  • maternal connective tissues

  • maternal endothelium

Endothelialchorial placentation

• Somewhat invasive, 4 layers

• Fetal layers

  • Fetal endothelium

  • fetal connective tissue

  • chorionic epithelium

• Maternal Layers

  • maternal endothelium

Hemochorial placentation

• Most invasive, 3 layers

• Fetal layers

  • Fetal endothelium

  • fetal connective tissue

  • chorionic epithelium

Diffuse placenta

• villi spread in small clumps over entire surface of chorion

• pigs, horses

Cotyledonary placenta

• Villi in scattered patches (cotyledons) across chorion

• Associated with maternal caruncles found on uterine endometrium

• ruminants

Placentome

• functional unit

• cotyledon+caruncle

Zonary placenta

• villi develop along band of chorion that encircles trunk of embryo

• dogs and cats

Umbilical cord

• Connection between fetus and placenta

• 2 umbilical arteries

• 1 umbilical vein (2 in placenta)

• Urachus

• wharton’s jelly

Umbilical arteries

• Deoxygenated blood

• bring blood from fetal caudal abdominal aorta to placenta

Umbilical veins

• Oxygenated blood

• bring blood from placenta to hepatic portal vein and ductus venosus

Urachus

• Carries waste from bladder to allantoic cavity

Ductus venosus

• Shunt the bypasses liver

• goes directly from umbilical vein to caudal vena cava

Ductus arteriosus

• Shunt that bypasses the lungs

• goes directly from pulmonary artery to aorta

Foramen ovale

• Opening between R and L atrium

• Some blood still flows from R atrium to ventricle and out pulmonary artery

Changes at parturition

• ductus venosus closes within hours to days

• foramen ovale closes in days due to decreased left atrial pressure

• urachus closes when cord broken

• ductus arteriosus closes within a few days

Eponychium

• Fairy fingers

• outer epidermal layer covering hooves

• protects uterus from damage

• helps tell if they have walked

Mammary gland function

• secrete milk to nourish offspring

• colostrum (first milk)

• enlarged modified sweat glands

Glandular portion of mammary gland

• Structure that creates and stores the milk

Teat

• protrusion that allows offspring to obtain milk

Alveoli

• grape-like clusters of milk secreting cells

Mlik ducts

• large ducts in glandular portion that carry milk from alveoli to cistern

Cistern

• storage cavity

• gland cistern and teat cistern

Teat canal

• duct that leads from teat sinus to teat opening

Teat sphincter

• exit point for milk

• keeps milk in and pathogens out

Mammary gland comparative anatomy

• Cow/doe/ewe- single teat canal and single teat opening

• Mare/sow- two teat canals, two teat openings per teat

• Bitch/cat- multiple teat canals, multiple teat openings per teat

Functions of nervous system

• Perception of environment

• Integration and processing of environmental information

• Response to environment

  • Voluntary and involuntary

Central Nervous System (CNS)

• Brain and spinal cord

• Integration and processing of information

• Incapable of true regeneration

Peripheral Nervous System (PNS)

• Cranial and spinal nerves that spread to rest of body

• Sensation and movement

Afferent component of PNS

• Sensory

• Carries info from extremities to spinal cord and brain

Efferent component of PNS

• Motor

• Carries info away from spinal cord and brain, to extremities

Somatic Nervous System

• Conscious activity

• Nerves of skin and muscles

• Sensory and motor function

Autonomic Nervous system

• Unconscious activity

• Heart, GI tract, etc

• Sensory and motor function

Functions of afferent system

• Sensation of different categories of stimuli

  • Pressure

  • Stretch

  • Temperature

  • Noxious (discomfort, pain)

• Special categories limited to the head

  • Vision

  • Audition

  • Taste

  • Olfaction

  • Balance

Neuron

• Nerve cell

  • Just like every other cell with a nucleus, cell membrane, etc

• 4 distinct parts

  • Soma

  • Dendrites

  • Axon

  • Axon Terminals/ Synaptic knobs

Soma

• Cell body where nucleus and other organelles are contained

• Sends and receives information

Dendrites

• Projections from soma

• Receives and transmits electrical impulses, brings to soma

• Where they come together at the soma is where info is processed

Axon

• single projection from soma

• Transmit signals away from soma, to another cell

• New impulses generated at spot where soma and axon come together

• Covered in myelin

Axon Terminal/ synaptic bulbs

• Specialized ending of axon

• Interacts with next cell to transmit information

Synapse

• Axon terminal converts electrical signal to a chemical signal- a neurotransmitter

• Pre-synaptic neuron releases neurotransmitter into synaptic cleft

• Neurotransmitter received by post-synaptic neuron or other type of cell

Myelin

• Insulated sheath formed around nerve projections

  • Axon

  • Dendrites

• Provided by supportive cells which differ based on location

  • Oligodendrocytes- CNS

  • Schwann Cells- PNS

• Increase speed of electrical impulses

White matter

• Regions of CNS where nerves are myelinated

  • Internal region of brain

  • External region of spinal cord

Gray matter

• Region of CNS where nerves are not myelinated

  • External region of brain

  • Internal region of spinal cord