Human Physiology Flashcards
2 Tasks of the Human Digestive System
- Breaking down large food molecules into smaller, usable, molecules
- Absorbing these smaller molecules
Mouth and Digestion
Mechanical digestion (teeth cut)
Chemical digestion (salivary amylase)
Salivary Amylase
Enzyme in the mouth (saliva) that starts chemical digestion
Esophagus
No digestion occurs here
Transports food from throat to stomach
Epiglottis
a flap of catilage at the back of the throat that directs food away from the windpipe and into esophagus
Pharynx
fancy word for throat
Stomach
Protein digestion begins here
Stomachs thick muscular walls churns food which secretes gas to break them down
Pepsinogen
Found in the stomach
Inactive form of the enzyme PEPSIN which breaks down proteins
pH in the stomach
Acidic
Between 2-3
What causes an ulcer?
Excessive acid in the stomach
Small Intestine
Digestion is completed here (last digest)
pH is 8
Small intestine is 6 meters longs
Intestinal enzymes
Amylases
Proteases
Lipases
Nucleases
Peptidases
Break down proteins in small intestine
Makes sense because of peptide bond
Villi
Fingerlike projections that line the small intestine
Absorb nutrients
Have microvilli that further enhance the rate of absorption
Liver
produces bile that emulsifies fats
recycles red blood cells
detoxs drugs and alcohol
produces cholesterol
produces nitrogenous waste: urea
pH of Bile
11
Gallbladder
stores bile that was produced by liver
Vestigal structure (don’t need it to survive)
Pancreas
- Produces enzymes
- Produces sodium bicarbonate
- Produces hormones to control blood sugar levels
Sodium bicarbonate
Produced in the pancreas
Neutralizes stomach acid to allow enzymes a BASIC environment to function
Large Intestine
Colon
No digestion occurs here
- Egestion: removes undigested waste
- Vitamin production
- Reabsoption of water
Reabsoption of water
Takes place in the large intestine
If there is too much water reabsorbed=constipation
If not enough water is reabsorbed=diarrhea
Rectum
Last 7 to 8 inches of the gastrointestinal tract which stores feces
What happens when air enters the nasal cavity
It is moistened, warmed, and filtered
Alveoli
Tiny air sacs in the lung where cellular respiration takes place
How is air drawn into the lungs?
Negative pressure
Medulla
Part of the brain that sets the breathing rhythm by monitoring CO2 levels and pH levels in blood
How is oxygen carried in the human blood?
By hemoglobin
Combines with oxygen molecules to form oxyhemoglobin
How is CO2 carried in the human blood?
Dissolved in the blood and is carried as part of plasma
Carbonic acid-bicarbonate ion system
pH of the human blood
7.4
Artery
Carries blood away from the heart
Vein
Carries blood back to the heart
Capillary
Allows for diffusion of nutrients and wastes between cells and blood
Blood
Different types of cells suspended in a liquid matrix called plasma
4 to 6 liters in average body
Serum
Blood plasma minus the clotting factors
What does your body need to clot?
Calcium
Plasma
Liquid portion of the blood
Red blood cells
Carry hemoglobin and oxygen
Formed in bone marrow
Live about 120 days
no nucleus
White blood cells
Fight infection
formed in bone marrrow
die fighting infection
Platelets
clot blood
cell fragments
How many beats per minute does the heart do?
70
pumps 5 liters too
Atria
Recieve blood from the cells