Digestive & Urinary System

Digestive System

Gastrointestinal, alimentary canal, or digestive tract-continuous tube running from mouth to anus for passage of food

Accessory Organ-Supply secretions such as enzymes, saliva, mucus, etc.; aiding in the breakdown of food

Digestive Processes

Ingestion-taking in of food through the mouth

Propulsion and Segmentation- forward movement and mixing of food down the GI tract

Peristalsis-propulsion by contraction and relaxation of smooth muscles lining the alimentary canal

Digestion-process of breaking down larger food molecules into smaller molecules

Mechanical digestion-physical breakdown of food by cutting and grinding

Chemical digestion-requires enzymes

Absorption-Transport of digested end product into blood and lymph through the wall of GI tract

Defecation-elimination of indigestible substances

Wall of GI tract

Mucosa

Submuscosa

Muscularis or muscular layer

Serosa-outer covering of the GI tract

Mucous membrane-produces mucus for reduction of friction and protections

Epithelium-varies by location, nonkeratinized stratified squamous in mouth, esophagus and anus, protection against friction

Muscularis mucosae-two twin

Areolar connective tissue containing major blood vessel, many elastic fibers to retain shape

Submucosal Plexus-autonomic nerve supply, glands and lymphatic tissue

Inner circular layer-squeeze, decrease size of lumen; in some areas act as sphincter or valves

Outer longitudinal layer-shortens intestine

sphincter-voluntary muscle, also external and sphincter is skeletal muscle

myenteric plexus-nerves

Serous Membrane-composed of thin layer of areolar connective tissue and simple squamous epithelium, produces serous fluid for lubrication

Alimentary Canal

Mouth-Opening into the oral cavity

Oral Cavity-area enclosed by the teeth and lips

Pharynx

Oropharynx-located posteriorly to mouth, passage for food, water and air

Larnyngopharynx-inferior to oropharynx, involved in deglutition, forcing bolus from mouth to esophagus

Esophagus-collapsible tube runs from the pharynx to stomach, pass through diaphragm, food transported by peristalsis, no digestive function, only passage for food

Stomach-located left of the abdominal cavity in left hypochondriac region, food enters at the cardio esophageal sphincter, food empties into duodenum of small intestine at the pyloric sphincter

Rugae-internal folds of stomach mucosa, storage tank for food, food mixes with gastric juice to make chyme

Regions

Cardiac region-near heart

Fundus-dome shaped, filled with gas

Body-main portion

Pylorus-funnels shaped end

Pyloric Sphincter-controls food leaving stomach and entering small intestine, only absorption that occurs is water, alcohol, some vitamins, and aspirin

Small intestine-Muscular tube extending from the pyloric sphincter to the ileocecal valve, chemical digestion of fat begins

Regions

Duodenum-first portion of Si attached to stomach chemical digestion

Jejunum-middle section, main site of nutrient absorption

ileum-end portion, connected to cecum, some absorption

Villi of SI-fingerlike structures that increase surface area for absorption

Large Intestine-site of absorption of water and electrolytes; produces vitamins, eliminates indigestible food from body as feces

Regions

Cecum-first out pocketing of the LI; attached to small intestine; site of appendix attachment

Colon-ascending, transverse, descending, and sigmoid colon

Rectum-stores feces until it is defecated

Feature-contains tenia coli

Haustra-bulges or pockets along LI

Anus-Eliminates feces from rectum to exterior, defecation controlled by sphincters

Internal- made of involuntary smooth muscle

External-voluntary skeletal muscle, presence of feces in rectum triggers defecation reflex

Teeth-hardest substance in the body, functions to mechanically breaks down food into smaller pieces

Enamel-hard outer layer of teeth

Dentin-middle layer of bone-like living tissue under enamel

Pulp-softer inner structure, contains nerves and blood vessel, supporting ligament, connective tissue that attaches teeth to jaw bone

Gingiva-gums

regions

crown-part of tooth above gums

root-anchored under gums

types

deciduous-baby teeth ( 20 )

permanent-adult teeth ( 32 )

Incisors-most anterior, for cutting

cuspids or canines-lateral to incisor; for tearing and shredding

premolar and molars-sides and back teeth; grinding

Salivary glands- produces saliva to moistens food into bolus

Lamina Propria-areolar connective tissue, contains blood and lymphatic vessels and lymph node for nourishment and immunity

Gastric Glands

Goblet Cells-produce muscus

chief cells-produce pepsinogen

Pepsinogen-in presence of hydrochloric acid converts pepsinogen to pepsin

Pepsin-protein digesting enzyme in stomach

Parietal cells-produces HCI and intrinsic factor

Intrinsic factor-needed for absorption vitamin B 12 in stomach

Urinary System Pt 1

Kidneys-regulating your water volume, concentrations, and PH levels, influencing your red blood cell production and blood pressure

Renal cortex-outermost

Renal Medulla-a set of cone-shaped masses of tissue that secrete urine into tiny sac-like tubules

Renal Pelvis-innermost, a funnel shape tube surrounded by smooth muscle that uses peristalsis to move urine out of the kidney into the water and into the bladder

Urinary System Pt 2

Urination-all mammals, most animals, urinate to remove Toxins and to help maintain water-volume Homeostasis or blood pressure

Urine-5% Solutes 95% water contains over 3000 different chemical compounds, and their varying levels of concentration

Leukocytes: Pyuria Urinary tract infection

Glucose-glycosuria diabetes mellitus

Erythrocytes-hematuria bleeding in the urinary tract