ANATOMY AND PHYSIOLOGY (RVT) FINAL PART 4

Gastrointestinal System

A tube system from mouth to anus aiding digestion and nutrient absorption; also known as the digestive tract, GI tract, alimentary system, or gut.

Accessory Digestive Organs

Aid in digestion and absorption. Examples include salivary glands, liver, and pancreas.

Skeletal Muscle in GI Tract

Located in the mouth, pharynx, cranial esophagus, and external anal sphincter, under voluntary control.

Smooth Muscle in GI Tract

Found in the rest of the digestive tube (esophagus, stomach, intestines, internal anal sphincter). Arranged in circular and longitudinal layers.

Prehension

Grasping food with lips or teeth.

Mastication

Chewing, the mechanical grinding and breaking down of food.

Digestion

Breakdown of complex foods into simple nutrient molecules.

Absorption

Simple nutrients absorbed into the bloodstream for use by the body’s cells.

Herbivores

Plant-eating animals (e.g., cattle, sheep, goats).

Carnivores

Meat-eating animals (e.g., cats).

Omnivores

Plant material and meat-eating animals (e.g., pigs, humans).

Oral Cavity

Also known as the buccal cavity; where food is initially taken in and digestion begins.

Salivary Glands

Glands that produce saliva for digestive and lubrication functions (parotid, mandibular, sublingual).

Parotid Glands

Located ventral to the ear.

Mandibular Glands

Located ventral to the parotid glands at the caudal angle of the mandible.

Sublingual Glands

Located medial to the mandible just under the base of the tongue.

Maxilla and Incisive Bones

The upper arcade of teeth is contained in what?

Mandible

The lower arcade of teeth is contained in what?

Incisors

Grasping teeth.

Canines

Tearing teeth.

Premolars

Cutting teeth.

Molars

Grinding teeth.

Lingual Teeth Surface

Inner surface of the lower arcade that faces the tongue.

Palatal Teeth Surface

Inner surface of the upper arcade that faces the hard palate.

Labial Teeth Surface

Outer surface of the upper and lower arcade at rostral end of mouth.

Buccal Teeth Surface

Outer surface of the teeth more caudal in the mouth facing the cheeks.

Incisal Teeth Surface

Biting edge of anterior teeth.

Occlusal Teeth Surface

Chewing edge of posterior teeth.

Carnassial Teeth

1st molar in the lower arcade and the 4th premolar in the upper arcade of ruminants.

Dental Formula

Represents the number of each type of tooth found on one side of the upper and lower jaws.

Pharynx (Throat)

Part of both GI and respiratory tracts; swallowing sends food from the oral cavity to the esophagus.

Esophagus

Muscular tube that extends from the pharynx to the stomach, transporting swallowed material.

Peritoneum

Serous membranes found in the abdominal cavity that include the visceral peritoneum, parietal peritoneum, mesentery, and omentum.

Parietal Peritoneum

Covers the abdominal wall and diaphragm.

Visceral Peritoneum

Covers the abdominal organs.

Mesentery

Attaches the intestine to the abdominal wall and holds it in place; contains blood vessels, lymph vessels, and nerves.

Omentum

Two layers of fatty tissue; greater omentum (fat storage, immune regulation, tissue healing) and lesser omentum (connects stomach to other organs).

Stomach Functions

Storage of ingested food, mechanical and chemical breakdown of food.

Chyme

Digested stomach contents in semi-liquid form.

Monogastric

Animals with single stomachs (AKA simple-stomach).

Ruminants

Animals with mixing and fermentation compartments in addition to the stomach.

Cardia

Area immediately surrounding the opening from the esophagus into the stomach.

Cardiac sphincter

Circular smooth muscle surrounding the cardia, closing off to reduce reflux.

Fundus

Section of the stomach that forms a distensible, blind pouch that expands as more food is swallowed.

Body (Stomach)

The “middle” of the stomach, rich with glands.

Pyloric antrum

Distal part of the stomach; grinds up food and regulates hydrochloric acid production.

Pylorus

Muscular sphincter that regulates movement of chyme from the stomach into the duodenum and prevents backflow.

Abomasum

The 'true stomach' of the ruminant lined with glandular tissue.

Rumen “Paunch”

Large fermentation vat where microorganisms turn carbohydrates into usable energy.

Rumination

When ruminates swallow their food and bring it back up the esophagus to their mouth this process it called?

Reticulum “Honeycomb”

Smallest and most cranial compartment of the forestomach compartments of the ruminant.

Omasum “Many Plies”

Breaks down food particles further, absorbs volatile fatty acids, removes bicarbonate ions, and absorbs water.

Duodenum

First short segment of the small intestine that leaves the stomach.

Jejunum

Longest portion that makes up most of the small intestine.

Ileum

Short segment connecting to the colon of the large intestine, separated by the ileocecal sphincter.

Villi

Folds in the intestinal wall and millions of tiny, cylindrical projections.

Microvilli

Tiny projections on villi that microscopically resemble short bristles on a brush.

Crypts

Invaginations in the intestinal mucosa that constantly produce cells to replace older cells.

Peristalsis

Circular muscle contractions that move like waves, propelling contents along the GI tract.

Segmentation

Circular muscle contractions in different adjacent sites that cause back-and-forth mixing movements.

Four Structures of the Large Intestine

Cecum, colon, rectum, and anus.

Cecum (Blind Sac)

Located at the ileocecal junction, poorly developed in carnivores, more developed in ruminants.

Rectum and Anus

Terminal portion of the large intestine with sensory receptors that stimulate the defecation response.

Liver

Filters materials absorbed from the GI tract and produces bile acids.

Gallbladder

Concentrates and stores bile until needed.

Pancreas

Secretes bicarbonate into the duodenum to neutralize acid contents.

Enzymes

Proteins that speed up chemical reactions that split complex food molecules into simpler compounds.

Amylase

Breaks down amylose, a sugar component of starch.

Lipase

Digests lipids.

Enzymes

Proteins that speed up chemical reactions that split complex food molecules into simpler compounds.

Nutrients

Substances derived from food necessary to carry out all normal body functions (water, carbohydrates, lipids, proteins, vitamins, minerals).

Carbohydrates

Divided into sugars (monosaccharides, disaccharides), starches (polysaccharides), and cellulose (polysaccharides).

Glucose

Fundamental building block molecule that results from large carbohydrates break down

ATP

The major fuel for the body (cell energy needs).

Fats (Lipids)

Soluble in other lipids and in organic solvents, includes neutral fats, phospholipids, steroids, and other lipid substances.

Amino Acids

Essential amino acids must be present in the diet because the animal either cannot make them at all or cannot make them fast enough to meet the body’s needs for tissue maintenance and growth.

Vitamins

Act as coenzymes or parts of coenzymes, activating enzymes for metabolic reactions.

Minerals

Inorganic substances that are essential for life, classified as macro minerals, microminerals, and trace elements.

Catabolism

Breaking down nutrients into smaller molecules to provide energy.

Anabolism

Using stored energy to assemble new molecules from small components produced from catabolism.

Diploid Chromosomes

Body cells (non-reproductive); contains identical chromosomes, which occur in pairs; always have an even number; identified as 2n.

Haploid Chromosomes

Reproductive cells; undergo meiosis; do not contain identical chromosomes; total # of chromosomes in each daughter cell is reduced to ½ the number of the parent cell

Mitosis

Cell division where chromosomes duplicate and half go to each daughter cell, resulting in identical genetic makeup to each other and the parent cell.

Meiosis

Cell division where chromosomes do not duplicate before division, half go to each daughter cell randomly; produces ova and spermatozoa.

Sex Chromosomes

XX: Individual is genetically female; XY: Individual is genetically male

Spermatogenesis

Production of male sex cells; occurs in seminiferous tubules of the testes.

Oogenesis

Production of female sex cells; occurs in ovarian follicles.

Testes

The male gonads; where male reproductive cells are formed; Produce sperm and hormones, housed in the scrotum.

Testosterone

The principal androgen produced by the testes; responsible for male secondary sex characteristics and anabolic effects.

Spermatozoa

Long, thin cells with three main parts: an enlarged head, a midpiece, and a long and narrow tail.

Scrotum

Sac of skin that houses the testes and helps regulate their temperature.

Spermatic Cords

Link the testes with the rest of the body; Contain blood vessels, nerves, lymphatic vessels, and vas deferens

Pampiniform plexus

Heat-exchange mechanism in the spermatic cord that helps maintain testes at a slightly lower temperature.

Seminiferous Tubules

Site of spermatogenesis; long, convoluted U-shaped tube attached to the rete testis.

Interstitial cells

Endocrine cells between the seminiferous tubules that produce androgens.

Epididymis

Single, long, convoluted tube that connects the efferent ducts of the testis with the vas deferens; responsible for storage and maturation of spermatozoa.

Vas Deferens

Muscular tube that connects the tail of the epididymis with the pelvic portion of the urethra; moves spermatozoa to the urethra during ejaculation form semen.

Accessory Reproductive Glands

Glands that produce alkaline fluid that helps counteract the acidity of the female reproductive tract

Penis

Male breeding organ composed of muscle, erectile tissue, connective tissue, a large blood supply, and many sensory nerve endings.

Sigmoid Flexure

S shape of non-erect penis of the bull, ram, and boar.