Veterinary Anatomy #3

Name/state common features of endocrine glands

 - The endocrine system differs from other in
that the component organs/glands are not in
direct continuity
• Hormone synthesis is a common function for
all endocrine glands

• Extensive blood supply

• Absence of secretory ducts

• Deliver their secretory products (hormones)
into the blood, lymph or tissue fluid.

• Collaborate with nervous system to maintain
the homeostasis.

• Hormones effect are slow compare with nerve system but last longer.

Name/state the primary endocrine organs

- Hypophysis (Pituitary gland)
• Pineal gland (formerly epiphysis)
• Thyroid glands
• Parathyroid glands
• Adrenal glands

Identify the hypophysis conformation and position in the cranial cavity

Occupies a central depression of the sella turcica of basisphenoid, known as the hypophyseal fossa

Formed by two parts: Adenohypophysis and neurohypophysis

Define sella turcica and hypophyseal fossa

Saddle-shaped depression in the basisphenoid bone of the skull that houses the pituitary gland

Hypophyseal fossa is a sunken central part of the sella turcica where the pituitary gland is physically located

Describe the communicating routes among hypothalamus and adenoohypophysis and neurohypophysis

Hypothalamus and adenohypophysis are connected by a hypophyseal portal vascular system

Hypothalamus and neurohypophysis are connected by a neural stem

what is circled in this image

hypothalamus

Describe the pineal gland

Produces melatonin, a hormone that modulates sleep patterns in both circadian and seasonal cycles

Shape of the gland resembles a pine cone

Identify its position in the encephalon

Located in the middle of the encephalon. In the area known as diencephalon. Caudo-dorsal to the thalamus

Describe the conformation and location of the thyroid glands

• Produce thyroxine hormones T3 & T4
• In most dogs is a paired gland (right & left)
nevertheless each gland can be referred as a lobe.
• Lies lateral to the trachea caudal to the larynx (sometimes overlapping the larynx)

Describe the location of parathyroid glands, be able to differentiate it from thyroid gland tissue

• Produce parathyroid hormones
• Normally four, 2 in each side
• In dogs and cats normally are embedded in the thyroid gland
• Frequently scape notice during a dissection.
• Parathyroid glands are pale contrasting with the red-brick color of thyroid glands,

Adrenal glands produce what critical hormone? and regular hormones

• Cortisol

• Aldosterone

• Epinephrine

• Androgens

Cortisol effects with body system/organ

• Muscle

• bone

• skin

• immune system

• vascular system

• central nervous system

• liver

• kidney

Adrenal gland location

• Retroperitoneal

• Craniomedially to kidney’s cranial pole

• Small size compared to kidneys

HIDDEN BY FAT

Conformation of adrenal glands

• Capsule 

• Cortex

• Medulla

Exocrine glands function?

Exocrine glands release (secrete) substances through opening (ducts) onto your body external surfaces or within cavity surface

• Sweat

• Lacrima

• Saliva

• Digestive juices

• Milk

Describe the mammary glands

• Subcutaneous, enlarges sweat glands

• Produced colostrum and milk

• Each gland is separated by a CT septa

• Develop in the mammary ridges, the ridges extend from axilla to inguinal regions

• Each gland secretes via a teat or papilla

• Each teat can secret via one or multiple papillary ducts

Mammary glands in dogs and cats

• Dogs normally have five pairs of mammary glands. Cats have four pairs

• Each gland has 10-12 openings in dogs

• 4-8 in cats

Describe the lymphatic drainage in mammary glands

Axillary and accessory axillary lymph nodes: 

• Both thoracic mammary glands and cranial abdominal mammary glands

Superficial inguinal lymph nodes: 

• Both cranial and caudal abdominal mammary glands and inguinal mammary glands

Name the tunics (coats) of the gastrointestinal tract

Serous coat - visceral peritoneum

Muscular coat - longitudinal and circular layers

Mucous coat - most internal has glands absorbs

Submucous coat - In between muscle and mucous layer

When esophagus joins with stomach in dogs it creates what structure?

Cardia sphincter - IT IS AN ANATOMICAL STRUCTURE AND NOT A FUNCTIONAL STRUCTURE

What is pylorus

enlarges smooth mm. that regulated the pass of content from stomach to the small intestine

Fundus location

Very dorsal and left normally touch the spleen and walls and hypochondrium

How does gastric dilation and volvulus, also known as bloat, occur?

Since stomach doesn’t have super strong ligaments → flipping the stomach = entrance and exit twisted and vessel twisted

what does the superficial leaf contain and what does the deep leaf contain

• Superficial - contains spleen

• Deep - contains left limb of pancreas

what structures arises from the dorsal mesentery

Dorsal mesentery
– Dorsal mesogastrium (greater omentum)
– Mesoduodenum
– Mesojejunum
– Mesoileum
– Mesocolon
– Mesorectum

what structures arises from the ventral mesentery

Ventral mesentery
– Ventral mesogastrium (lesser omentum)
– Falciform ligament
– Median ligament of the bladder

Purpose of omental foramen

Entrance to omental bursa and boundaries

IN ORDER state the structures in the duodenum

Which is the most important structure

• Cranial part

• Cranial duodenal flexure

• Descending part

• Caudal duodenal flexure

• Ascending part

• Duodenojejunal flexure

What makes up the small intestine?

Duodenum

Jejunum

Ileum

What makes up the large intestine?

• Cecum

• Colon

• Rectum

• Anus

What is the greater omentum attached to?

Greature curvature of stomach + medial surface of spleen (hilus)

Where is the major duodenal papilla located and where duct(s) empty there

• Common bile duct - Bile going towards lumen of duodenum

• Pancreatic duct - Pancreatic juice towards small intestine

BOTH OPEN AT MAJOR DUODENUM PAPILLA at the descending portion

Where is the minor duodenal papilla located and where duct(s) empty there

Descending portion

• Accessory pancreatic duct

What structures help identify the ileum

• define by antimesenteric ileal artery and the ileocecal fold

• Ileocolic orifice

what is the ceceocolic orific?

Opening between the cecum and the ascending colon

what is the Ileocecal fold?

Plica of peritoneum between the cecum and the ileum

IN ORDER state the structure of the colon

• Ascending colon

• Right colic flexure

• Transverse colon

• Left colic flexure

• Descending colon

• Rectum

what is controlling the external anal sphincter?

Controlled by somatic NS

What is controlling the internal sphincter?

Controlled by autonomic NS

purpose of gall bladder

dispose of lipids

purpose of hepatic ducts

brings bile to the ducts

IN ORDER state the structures of biliary system

• gall bladder

• cystic duct

• hepatic ducts

• bile duct

• major duodenal papilla

purpose of cystic duct

duct that connect the gall bladder with the bile duct

purpose of bile duct

duct that carries the bile to the lumen of the descending duodenum. Opens into the major duodenal papilla.

name the ligaments that hold the liver in position

Right triangular ligament

left triangular ligament

coronary ligament

location of right triangular ligament

courses from the right crus of the diaphragm to the right lateral lobe of the liver

left triangular ligament location

courses from the left crus of the diaphragm to the left lateral lobe of the liver

coronary ligament location

courses between the diaphragm and liver around the caudal vena cava and hepatic veins

pancreas function

exocrine function - to produce pancreatic juice, rich in enzyme

pancreas location

• body

  • Near pylorus

• right lobe 

  • within mesoduodenum

• left lobe 

  • within deep leaf of greater omentum

spleen location

located within the superficial leaf of the greater omentum (attaches at the hilus)

what is the pelvic cavity composed of

• Levator ani muscle

• Coccygeus muscle

Name the pouches within the pelvic cavity (starting ventrally to dorsal)

• Pubovesicle pouch

• Vescogenital pouch

• Rectogenital pouch

• Pararectal fossa

what is the perineum? what structures does it surround

• Portion of the body wall that covers the pelvic outlet (caudal pelvic aperture)

• Surrounds the anus and terminal parts of the urogenital tracy

How can we determine sex of an animal when they are young?

Use the anogenital distance to determine sex

distinguish the perineal body and perineal region

• Perineal region is externally visible projection of the perineum on the skin

  • Anus, vulva

• The perineal body is the internal tissue located between rectum and urogenital organs

  • Between the anal canal and bulb of the penis

  • Median fibromuscular mass b/t the anus and vulva

function of the kidneys

Filters blood to detoxify and rid the body of waste

function of the ureters

transport urine from kidneys to bladder

function of urinary bladder

temporary storage of urine

function of urethra

eliminate urine

location of kidneys dog:

• Right → ventral to L1-L3 & recessed into the liver

  • Recessed/capped by the caudate process of the caudate lobe of the liver

• Left → ventral to L2-L4 

• Right kidney is ~ 3x the length of L2 vertebral body

Location of kidneys cat

• Kidney more mobile than the dog

• Right kidney cranial to left 

• 2.4 to 3x the length of L2 vertebral body

• May be shrunken in older cats

  • B/c CKD

Anatomy of kidney - dog and cat (from the outside)

• Convex lateral border

• Concave medial border → hilus

• Cranial pole 

• Caudal pole

• Dorsal & ventral surface

Name the first outer layer of kidney

• Surrounded by adipose capsule 

• Fibrous outer capsule - DICCT (dense irregular collagenous connective tissue)

  • Attaches to renal vessels and renal pelvis

location of renal sinus and its surrounding structure

• Renal sinus: cavity located at renal hilus

  • Surrounding renal pelvis

  • Filled with white adipose tissue

what is the renal pelvis and purpose of the renal pelvis

• Mucosa of the ureter expands into kidney, within the renal sinus 

• Funnel that is going to funnel urine from kidneys into ureter

what is the pelvic recesses

Diverticula of pelvis that extend into the renal parenchyma

what is the renal cortex

• Reddish-brown, granular appearance

  • Contains renal corpuscles

OUTER MOST PORTION

what is the renal medulla

INNERMOST/DEEPEST PART OF THE KIDNEY

• contains the renal crest

Renal pyramid conformation

• part of renal medulla

• base

• apex: papilla “fits” into renal pelvis

• papillary foramina on the renal crest

• fused as one pyramid on midline

State where the urine flows

• urine made in the renal cortex flow through renal pyramid to → renal papilla → renal crest → renal pelvis

Blood supply to the kidney (arteries)

Renal Aa → interlobar Aa → arcuate Aa →
interlobular Aa → afferent arterioles →
glomerulus → efferent arterioles

blood supply to the kidney (veins)

Stellate Vv → interlobular Vv → arcuate Vv → interlobar Vv → renal Vv

what unique feature on the kidneys do cats have

Subcapsular veins

Sympathetic innervation of the kidneys

from our splachnic nerves and a little bit of lumbar splachinic nerve

Parasympathetic innvervation of the kidneys

vagus nerve sends parasympathetic innervation to celiac mesenteric ganglion and plexus → down to kidney

why does the ureter enter the bladder dorsally at an oblique angle? why?

It is functional valve that is going to stop or slow the flow of the urine from the ureter into the bladder

define trigone

location of ureteral orifices and urethral orifice

what are the serosal attachments of the urinary bladder and what does each attachment contains

• Lateral ligaments of the bladder

  • Contains umbilical around of the bladder and ureter

• Median ligament of the bladder

  • Contains remnant of the fetal urachus

what is the urinary bladder made up of?

thick tunica muscularis 

• detrusor muscle - contracts urinary bladder (under ANS control)

How does the SNS and PSNS work in the urinary bladder

• SNS - inhibits bladder contraction

• PSNS - stimulates bladder contraction

main blood supply: urinary bladder

• Branches of the vaginal/prostatic a.

• Cranial vesicle (br. of umbilical a.)

Hypogastric nerve innervation of the urinary bladder

• SNS

• controls physiological sphincter at the neck of the urinary bladder 

name/list the nerve innervation of the urinary bladder

• hypogastric nerve (SNS)

• pelvic nerve (PSNS)

• pudendal nerve (Somatic)

Pudendal nerve innervation of the urinary bladder

• Somatic

• Urethralis muscle - you can choose to hold your pee

name the muscle surrounding the pelvic urethra

Surrounded by urethralis muscle

Function of urethralis muscle

• voluntary sphincter