BIO 224: Final Exam

TMCC, Dr. Doe

Functions of the digestive system

Disassembly line, Nutrient absorption, Waste removal

Organs of the alimentary canal

Oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine

Accessory organs of digestion

Teeth, tongue, salivary glands, gallbladder, liver, and pancrease

Composition of mucosa

Epithlium, lamina propria of areolar tissue, muscularis mucosae, and MALT

Composition of submucosa

Dense, irregular connective tissue. Binds mucosa to muscularis externa. Numerous blood vessels and lymphatic vessels.

Composition of Muscularis externa

In most areas of the digestive tract. Deep to the lamina propria. Smooth muscle and elastic fibers. Creates grooves and ridges in the epithelium

Composition of serosa

Covering muscular layer. Adventitia, a dense network of collagen fibers

Function of myenteric plexus

Coordinates motility

Function of submucosal plexus

Regulates digestive secretions

Process of digestive system

Ingestion, mechanical digestion/ propulsion, chemical digestion, secretion, absorption, and defecation

Peristalsis

Waves of muscular contractions that move a bolus along the length of the digestive tract in an oral to anal direction

Segmentation

Cycles of contraction that churn and fragment the bolus. Mixing contents with intestinal secretions

Process of absorption

Across digestive epithelium to interstitial fluid to the blood.

Local factors that regulate digestive function

PH, volume (stretching of walls), or chemical composition of intestinal contents. Stimulates the release of prostaglandins, histamine, and other cells that affect adjacent cells.

Function of oral cavity

Sensory analysis, mechanical digestion, lubrication, and limited chemical digestion

Function of tongue

Mechanical digestion by compression, abrasion, and distortion. Manipulation to assist in chewing and to prepare food for swallowing. Sensory analysis by touch, temperature, and taste receptors. Secretion of mucins and lingual lipase

Function of saliva

Cleaning oral surfaces. Moistening and lubricating food. Buffers oral pH near 7.0. Controlling population of bacteria. Dissolving chemicals that stimulate taste buds. Some chemical digestion of carbohydrates

Incisors

Blade-shaped. Used for clipping or cutting

Canines

Conical. Single, pointed cusp. Used for tearing or slashing

Premolars

Flatted crowns. Two prominent, rounded cusps. Used to crush, mash, and grind

Molars

Very large, flattened crowns. 4-5 prominent, rounded cusps. Used for crushing and grinding

Different regions of the pharynx

Oropharynx, Nasopharynx, Laryngopharynx

Esophagus structure

Nonkeratinized stratified squamous epithelium. Prominent folds. Adventitia

Esophagus function

Transport of food from pharynx to stomach through peristalsis

Three phases of swallowing

Buccal phase, Pharyngeal phase, Esophageal phase

Buccal Phase

First stage of swallowing. Food is chewed and turned into bolus

Pharyngeal Phase

Movement of bolus from back of mouth to pharynx and into esophagus

Esophageal Phase

Final stage of swallowing. Food/liquid propelled through esophagus

Functions of the stomach

Temporary storage of ingested food. Mechanical digestion. Chemical digestion of protein and lipids. Chyme production. Secretion of intrinsic factor

Stomach modifications

Rugae, prominent folds in mucosa that allows for expansion of gastric lumen. Muscularis externa, allows for stronger contractions aiding in mechanical digestion and mixing.

Parietal cells

Secretes intrinsic factors and HCL

Chief cells

Secretes pepsinogen, a zymogen. Pepsinogen is converted to pepsin by HCL. Pepsinogen is autocatalytic

Enteroendocrine cells

Produces 7 hormones. G cells produces gastrin stimulating contraction of the gastric wall. D cells release somatostatin which inhibits the release of gastrin

Chemical digestion of the stomach

Digestion of some lipids by lingual lipase. Proteins are denatured by HCL. Some proteins digested by pepsin. Nutrients are not absorbed in stomach

Three phases of gastric motility

Cephalic phase, gastric phase, intestinal phase

Cephalic phase

Thought, sight, smell, taste

Gastric phase

Food enters the stomach

Intestinal phase

Chyme entering the duodenum

Sections of small intestines

Duodenum, jejunum, ileum

Modifications of Small intestine

Circular folds and intestinal villi

Brush border enzyme

Integral membrane proteins on intestinal microvilli. Final stages of chemical digestion. Enteropeptidase activates pancreatic trypsinogen

Function of gastrin

Secreted by G cells, Promotes increased stomach motility. Stimulates production of acids and enzymes

Function of secretin

Released when chyme arrives in duodenum. Increases secretion of buffers by pancreas and bile by liver. Reduces gastric motility and secretory rates

Function of gastric inhibitory peptides (GIP)

Secreted when fat and carbohydrates enter small intestine

Function of Cholecystokinin CCK

Secreted when chyme arrives in duodenum. Accelerates pancreatic production and secretion of digestive enzymes. Relaxes hepatopancreatic sphincter and contract gallbladder. Slow gastric emptying and inhibits gastric secretion

Functions of large intestine

Absorption or reabsorption of water, salts, bile salts, and vitamins produced by bacteria. Compaction of intestinal contents into feces. Storage of fecal material prior to defecation

Importance of gut microbiome

Produce vitamins and metabolizes undigested materials

Vitamins produced by gut microbiome

Vitamin K, Biotin, Vitamin b5

Vitamins produced by gut microbiome: Vitamin K

Required by liver for synthesis of some clotting factors

Vitamins produced by gut microbiome: Biotin

Important for glucose metabolism

Vitamins produced by gut microbiome: Vitamin B5

Required for manufacture of steroid hormones and some neurotransmitter

Structure of Liver

Largest visceral organ and gland. Within right hypochondriac/epigastric region. Porta hepatis includes hepatic artery proper, hepatic portal vein, and common bile duct

Liver functions

Metabolic regulation, hematological regulation, bile production

Production and functions of bile

Bile salts participate in mechanical digestion of fats in the small intestine. Necessary because mechanical digestion in stomach creates large droplets. Enterhepatic circulation

Function of gallbladder

Stores and concentrates bile. Releases bile into the common bile duct and duodenum

Structure of pancreas

Lies posterior to stomach. Extends from duodenum towards spleen. Retroperitoneal, binds to posterior wall of abdominal cavity and wrapped in thin connective tissue capsule

Functions of pancreas

Producing and secreting enzymes that break down carbs, proteins, and fats to neutralize stomach acid. Stimulates the release of insulin and glucagon

Components of pancreatic juices

Water, electrolytes and digestive enzymes amylase, lipase and protease

Temperature control of the testies

Mechanisms of temperature control of the testies

Seminiferous tubules Structure

Structure of mature sperm

Composition of semen

Functions of the epididymus

Structure of penile erectile tissue

Function of penile erectile tissue

Role of GnRH in male reproduction

Role of FSH in male reproduction

Role of LH in in male reproduction

Role of testosterone in male reproduction

How many oocytes are formed in oogenesis

1

Structure of the uterine wall

Basal layer of endometrium

Function layer of endometrium

Source of lubrication for intercourse in men

Source of lubrication for intercourse in women