The Digestive System

Chapter 15

15.1

Functions: mechanical and

chemical breakdown of food

       *absorption of nutrients

Consists of alimentary canal

and accessory organs

Wall of the Alimentary Canal

15.2 Characteristics of the Canal

1.  Mucosa - protects tissues and carries absorption

2.  Submucosa - glands, blood vessels, nerves

3.  Muscular Layer - smooth muscle tissue, circular & longitudinal fibers, pushes food  (PERISTALSIS)

4.  Serosa (serous layer) - visceral perioneum, outer covering of the tube, lubricates surfaces (serous fluid)

Mixing Movements

Contractions mix food with digestive juices

 

Peristalsis - pushes food down the tube

Anatomy of the Mouth

Anatomy of a Tooth

Teeth

 

Incisors

Cuspid (canine)

Bicuspids

Molars

Salivary Glands Produces saliva for chemical digestion of starches- Basic to neutralize acid to prevent decay of tooth enamel

Pharynx 

 

“throat”

-Trachea and

esophagus meet

 

 

 

 

Esophagus

Muscular tube that transports food to your stomach5-7 seconds

STOMACHPrimary food digestion location-secrete enzymes and digestive juices, including hydrochloric acid

Stomach

Regions

•Cardiac•Fundic•Body (greater and

lesser curvature)•Pyloric

Stomach Lining

Gastric Juices contain acids that break down food  - secreted by gastric glands (can sometimes release causing acid reflux)

PEPSIN  - most important digestive enzyme for breaking down food   

 

Mucus prevents stomach from digesting itself 

Chyme - paste, after food has been broken down, released then into the duodenum via the pyloric sphincter valve

Rugae - folds within stomach

Gastric Pits contain glands to make juices 

PANCREAS - secretes insulin which breaks down sugars

Pancreatic Juice also breaks down fat

 Liver

 1 large right lobe  | 1 smaller left lobe

Liver - ducts and vessels

Hepatic duct --> to common bile duct

Hepatic portal vein - circulates blood throughout liver

Liver Functions1.  blood glucose levels2.  breakdown of lipids and fats3.  protein metabolism4.  stores vitamins5.  destroys damaged RBCs6.  removes toxins7.  secretes bile

Gall Bladder - under liver          cystic duct --> common bile duct          stores bile, digests fat                 *gallstones may form

 

Small Intestine

 

Starts at the pyloric sphincter

1.  Duodenum

2.  Jejunum

 

3.  Ileum

 

*Mesentery 

Membrane holds it together,  contains

blood vessels

Greater Omentum

a  "curtain-like" membrane that covers the intestines, stores fat and lays like a drape

Greater Omentum

Intestinal villi - increase surface area to absorb nutrients, connect to vessels

The main function of the small intestine is to secrete chemicals that break down food and carry the nutrients away in the blood stream.  In one word:

ABSORPTION

Large Intestine

 

Cecum 

 

Appendix

 

Colon (4 parts)

    Cecum    Ascending   

Transverse     Descending    

Sigmoid

 

 

Rectum

 

Anus

Function of Large IntestineSecretes mucus,  reabsorbs water, contains bacteria to aid in digestion  (intestinal flora)

Mass Movements (defecation) - removes undigested food

The main job is  WATER REABSORPTION...

1.  esophagus2.  liver3.  stomach4. pyloric sphincter5.  duodenum6.  pancreas7.  jejunum8.  ileum9.  cecum10. appendix11.  ascending colon12.  descending colon13.  sigmoid colong14.  anus

Nutrition

Gastric Bypass Surgery

http://www.hurtbyadoctor.com/Gastric-Bypass-Surgery-Malpractice-Lawsuits-Information-Home.htm

Colon Cancer

Colonoscopy is a screening technique to detect cancer. 

See Katie Couric's Colonoscopy

The Urinary System

Chapter 17

17.1 Introduction

-Cells produce waste that can become toxic if they accumulate

Functions•the urinary system removes salts

and nitrogenous wastes•maintains normal concentration of

water and electrolytes•maintains pH, controls red blood

cell production and blood pressure

Composition•consists of a pair of kidneys which remove

substances from the blood•ureters which transport urine from the kidneys

to the bladder•urinary bladder stores urine•urethra conveys urine to the outside of the

body

17.2 Kidneys•lie on either side of the

vertebral column deep in the abdominal cavity

•positioned behind the parietal peritoneum (retroperitoneally)

•lateral side is convex, medial is concave, kidneys sit in a depression called the renal sinus

•Entrance is called the HILUM

-superior end of the kidney forms a funnel shaped sac - renal pelvis-renal medulla = center of the kidney-renal cortex = outer shell around the medulla; the cortex appears granulated due to the presence of nephrons-renal arteries and veins supply blood to the kidneys

The nephron is the functional unit of the kidney

Renal Arteries & Veins

•Arteries attach to the abdominal aorta•Veins attach to the inferior vena cava

Interlobar arteries pass between the renal pyramidsAfferent arterioles lead to the nephrons

Parts of the Urinary System - The NEPHRON

NEPHRONS -  functional unit of the urinary systemQuick Analogy:  A nephron is to the urinary system as the _________________ is to the nervous system

-each kidney contains about 1 million nephrons-renal corpuscle: composed of a tangled cluster called a glomerulus which filters fluid

Pathway = glomerulus -> proximal tubulue --> nephron loop (also called loop of henle) --> distal tubule --> collecting duct --> ureter --> bladder

What blood vessel enters the glomerulus?

17.3 Urine Formation (section is abbreviated)

•glomerular filtration - urine formation begins, plasma is filtered

•tubular reabsorption - returns most of the fluid to the body

•tubular secretion - removes what is not needed; produces urine

Urine Composition

95 % Water

Contains urea and uric acid (characteristic smell)

Can contain trace amino acids

Urine may also contain other chemicals that can be detected.

Hormones present in a pregnant woman are detectable in urine

17.4 Urine Elimination•After urine forms in the nephrons,the ureters

(starting with the renal pelvis) carry the urine away to the bladder

•Bladder is an expandable structure that stores urine before it is eliminated from the body.

•Transitional epithelial cells change shape to allow for expansion and contraction.

Micturation = urination; as the bladder fills this reflex occurs though it is also under voluntary control

Urethra = tube carries urine to the outside of the body

Disorders of the Urinary System

Many urinary problems can be solved by drinking enough water.  So how much fluid does the average, healthy adult living in a temperate climate need? The Institute of Medicine determined that an adequate intake (AI) for men is roughly 3 liters (about 13 cups) of total beverages a day. The AI for women is 2.2 liters (about 9 cups) of total beverages a day.

Cystitis = bacteria enters the bladder or kidneys (kidney infection); more common in women because the urethra is shorter

Commonly known as a "bladder infection" UTI = urinary tract infection

Frequent  need to urinatePain in the abdomen Burning sensation during urinationCloudy, bad-smelling urineBlood in the urineLeaking urineLow back pain Fever and chillsNausea and poor appetite

Catheters In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel.   The process of inserting a catheter is catheterization.

Catheterization of the bladder is a common medical procedure, often performed by nurses