Human Body Systems PART 1

Lets Start!

DIGESTIVE SYSTEM

• We need nutrients.  We eat so that we can get the stuff we need.  
• The Human Being, along with most chordates, eat food through something called ingestion, and we then digest it.

Getting and Using Food

• Enzymes break down materials into useable particles.  There are a few specific ones.
• Amylase
• Produced in salivary glands and pancreas
• Digests starch into glucose and maltose.
• Likes pH of 7
• Protease
• Produced by stomach glands
• Digests protein into amino acids
• Likes pH of 3
• Example: Trypsin and Pepsin
• Lipase
• Secreted by pancreas
• Digests lipids into fatty acids
• Prefers pH of 7-8

Some Useful Terms

• Movement and Control
• Peristalsis: the rhythmic wave-like motion that forces food through system
• Sphincters
• Muscular, ring-like valves that regulate the passage of particles through system 
• When something passes by, one shuts so it doesn't flow backwards.
• Accessory Glands
• Places that do not touch food but are still part of the digestive process
• Salivary glands, pancreas, liver, gall bladder
• Secrete digestive juices
• Swallowing and not choking
• Epiglottis
• A flap that switches between covering the trachea (breathing) and esophagus (swallowing)
• Coughing forces stray particles out of trachea back where it needs to go.

Digestive Tract Order

• Mouth
• Mechanical digestion
• Teeth go crunch
• Chemical digestion
• Spit dissolves starch
• Mucin lubricates food so it's easier to swallow
• Buffers protect teeth from decay
• Some anti-bacterial properties
• Esophagus
• Food slowly goes doooown
• Water helps
• Stomach
• Mechanical Digestion
• Muscles grind down chunks
• Chemical Digestion
• Acid at pH3
• Gastric Acid
• Stores Food
• Can stretch to hold a hellofalot of food
• Disinfects food
• Low pH kills most bacteria, any it doesn't kill, it regurgitates
• Duodenum
• First section of small intestine- where most chemicals flow into
• Bile from liver and gallbladder flow in, and also pancreatic fluid
• Serves as a buffer between stomach and small intestine
• Small Intestine

• Chemical Digestion
• All that goop from the lower accessory glands
• Dem enzymes
• Absorption
• Over 6 metres long!
• Huge surface area
• Villi, and each cell of villi has little lumps too
• Absorbs most nutrients
• 3 Sections
• Duodenum, Jejunum, Ileum (what you usually consider SI)
• WHAT ISN'T ABSORBED!
• Bile pigment
• Epithelial cells
• Lignin (carb found in plants)
• Cellulose
• Human microflora (namely bacteria such as e. coli)
• Appendix
• Between intestines
• Relatively unknown in use, can be removed
• Possibly houses good digestive bacteria
• Reboots digestive system after illness
• Additional surface area for cellulose-rich diet of the distant past...
• Vestigal organ
• Large Intestine
• Reabsorbs water
• >90% water is reabsorbed!
• Not enough water: constipation
• Too much water: diarrhea
• Microflora: Bacteria that do stuff
• E. Coli
• Bacteria produce vitamins
• Vitamin K, biotin, folic acid, others
• Generate... gas.
• Rectum
• Eliminates Poo
• Does not use peristalsis
• general contraction- controlled

Liver

• Largest gland in the body
• Under diaphragm
• Only human organ that can totally self regenerate
• If you take out a chunk and plop it in someone else, it will grow a new liver
• Like a potato! /shot
• Anatomy
• 4 Lobes
• Major: left & right
• Minor: caudate & quadrate
• Ducts
• Common Hepatic
• *Hepatic anything refers to liver*!
• Cystic
• from gall bladder
• Common Bile
• Joins pancreatic duct at hepatopancreatic ampulla
• Bile always always always goes to duodenum!
• Blood Flow
• Hepatic Artery
• Brings oxygenated blood to liver
• Hepatic Vein
• ...carries deoxygenated blood away from liver.
• Hepatic Portal Vein
• !!! Brings deoxygenated blood from small intestine
• All the oxygen went to the intestine, but none of the nutrients!
• Divides into smaller vessels called Sinusoids!
• Drain into central vein of the lobule
• Eventually drains into hepatic vein
• Drains into inferior vena cava
• Bile Production
• Hepatocytes (liver cells) secrete bile
• Secreted into the canaliculi
• To the bile ductules
• To common bile duct
• To gallbladder
• To the other bile duct
• To duodenum (small intestine)
• Gallbladder
• Thin-walled green thing that's right under the liver
• Stores bile
• Not... totally needed.  You can live without it if you make dietary modifications
• Functions of the Liver
• Has like 200 functions, but there are some main ones:
• Regulating blood glucose and glycogen
• Storage of nutrients
• including iron, Vitamin A, and Vitamin D
• Breakdown of erythrocytes
• Bile secretion
• Synthesis of plasma proteins
• including globulins, albumin, prothrombin, and fibrinogen
• Synthesis of cholesterol
• Detox
• Normal blood glucose = 90 mg/100 mL
• Liver pulls excess glucose from blood plasma and stores it as glycogen
• Adjusts amino acid levels in blood
• Excess amino acids are deaminated and excreted through the kidney
• What gets broken down?
• Insulin and other hormones
• Hemoglobin
• Toxic stuff
• Alcohol and drugs
• Even though toxins are broken down, they still damage the cells... so DON'T DO DRUGS
• Antibiotics and, er, hormones
• Ammoinia to urea
• Waste crud is excreted through kidneys
• Erythrocyte (red blood cells!) Breakdown
• Red blood cells have a lifespan of 120 days
• Weaken and rupture, like a tyre, release hemoglobin into bloodstream
• Hemoglobin is absorbed by kuppfer cells in the liver
• Split into groups:
• HEME GROUP (pronounced hemmy)
• Iron is removed from heme
• used to make new RBC's
• Remaining stuff is put into bilirubin
• become bile pigment
• Globins are hydrolyzed into amino acids and returned to blood

CIRCULATORY SYSTEM

• Why is there a circulatory system?
• Exchange of various necessary particles in the body
• Basically, the highway for the chordate body
• What is exchanged?
• Nutrients and fuels
• Respiratory Gases
• Oxygen and Carbon Dioxide from lungs/gills
• Intracellular waste
• Protective agents
• Platelets and White Blood Cells
• Regulating hormones
• Parts of the system:

• Blood (almost always red in chordates)
• Blood vessels
• Some variety of a pump
• Chordate Cardiovascular System
• Chambered Heart
• Atria (left and right)= Receives blood
• Ventricles (left and right) =Pump out blood
• Blood Vessels
• Arteries- carry blood away from heart
• Veins- carry blood towards the heart
• Capillaries- thin vessels that do all the exchange with cells
• Blood!
• Four main components to the blood in your body
• Erythrocytes
• Red Blood Cells, carry oxygen
• Leukocyte
• White blood cells
• Fight infection
• Non specific immunity
• Lymphocytes
• Specific immunity
• Platelets
• Clottin'
• Plaaaaasmaaaa
• That fluid goop
• Transmits heat