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bio test: 5-15-19

Terms in this set (82)

four phases of digestive system
1. Ingestion
2. Digestion
3. Absorption
4. Elimination
ingestion
take food into the body
digestion
break down the food
absorption
nutrients absorbed
elimination
undigested material/waste
two ways in which digestion occurs
1. mechanical
2. chemical
mechanical digestion
food is broken down into smaller pieces
- mouth (chewing... mastication)
- stomach (churn and grind food)
chemical digestion
- food is broken down from large molecules to smaller molecules (by enzymes)
- starts in the mouth, happens in the stomach, happens in the small intestine
how does the mouth contribute to digestion
- chews food
- salivary glands release saliva
- creates a structure called the bolus
what role does saliva have in digestion
- contains amylase (enzyme that breaks down starch)
- contains lysozyme (prevents infection)
what is a bolus
partially digested ball of food
esophagus
- tube that connects the mouth and stomach
- peristalsis
- epiglottis
peristalsis
contractions that push the bolus down through the esophagus
epiglottis
- flap of cartilage that covers the trachea when swallowing
- prevents choking
dysphasia
difficulty swallowing
stomach
- mechanical digestion
- chemical digestion
- digested food is broken down into chyme
mechanical digestion in the stomach
churning of bolus
chemical digestion in the stomach
secretes gastric juice (mixture of enzymes, mucus, HCl)
chyme
nutrient rich liquid
small intestines
- long tube
- 2 functions
2 functions of the small intestine
1. chemical digestion
2. absorption of nutrients
chemical digestion in the small intestine
happens in the duodenum
- uses the pancreas and the liver
pancreas role in chemical digestion in the small intestine
- secrete digestive enzymes that break down proteins, lipids, and nucleic acids
- secretes a base (sodium bicarbonate) to neutralize the acidic chyme
liver role in chemical digestion in the small intestine
produces bile
- breaks down fats into small droplets
- stored in the gallbladder
absorption of nutrients in the small intestine
contains folds called villi that increase surface area for more absorption
large intestine
also called the colon
- about 5 feet long with a diameter the size of a quarter
- reabsorption of water
- what is left is feces (stored in the rectum for elimination)
how does blood flow through the body
through double circulation
what is double circulation
1. pulmonary circuit (lungs)
2. systemic circuit (everything else)
three major types of blood vessels
1. arteries
2. veins
3. capillaries
arteries
- carry blood away from the heart
- thicker walls (surrounded by muscle)
- can contract to pump blood
- usually carry oxygenated blood
veins
- carry blood to the heart
- thinner walls (less muscle so cannot contract)
- have one way valves to prevent blood from going in the wrong direction
capillaries
- carry oxygenated blood to cells and deoxygenated blood away from cells
- very narrow (red blood cells move in single file)
pulmonary circuit
blood vessels that carry blood to and from the lungs
- right side of the heart
- pulmonary arteries
- pulmonary veins
- pulmonary capillaries
pulmonary arteries
carry deoxygenated blood because they are going to the lungs to get oxygen
pulmonary veins
carry oxygenated blood because they have just been oxygenated at the lungs
pulmonary capillaries
surround the structure in your lungs called alveoli
systemic circuit
blood vessels that carry blood to and from the rest of the body
- left side of the heart
- aorta
- superior vena cava
- inferior vena cava
aorta
- largest artery in the body
- carry oxygenated blood from the heart to the rest of the body
superior vena cava
vein that carries deoxygenated blood from upper body to the heart
inferior vena cava
vein that carries deoxygenated blood from the lower body to the heart
the heart
made up of two chambers
two chambers in the heart
- atria
- ventricles
atria (atrium singular)
- 2 atria in a human heart
- receive blood
ventricles
- 2 ventricles in the human heart
- thicker walls (more muscle) because they pump blood out of the heart to the rest of the body
two types of pumping blood
- systole
- diastole
systole
when the heart contracts and pumps blood
diastole
when the heart relaxes and chambers fill with blood
contents of blood
- 45% cells
- suspended in a liquid called plasma
what is the plasma in blood made up of
- 90% water
- proteins (blood clotting and immune system)
- nutrients, waste, CO2, O2, hormones
- cells fragments called platelets (used for clotting)
what types of cells are in your blood
- red blood cells
- white blood cells
- cell fragments called platelets
red blood cells
- called erythrocytes
- responsible for carrying the O2 and CO2
- biconcave shape (increase surface area)
- single drop of blood (0.5 mL) has 25 million red blood cells
white blood cells
- called leukocytes
- 5 different types
- fight infections
how does gas exchange occur
take in O2, breathe out CO2
path of oxygen
- breathe in through the nose/mouth (filtered by hair in nostrils and is also humidified and warmed)
- travels to pharynx
- air goes over the larynx
- goes through the trachea which then splits into two bronchi
- bronchi branch out into bronchioles
- at the end of each bronchiole are air sacs
pharynx
space at the back of the mouth above the esophagus and trachea
larynx
voice box that contains vocal cords
alveoli
- air sacs at the end of each bronchiole
- increase SA for gas exchange
right atrium
...
right ventricle
...
left atrium
...
left ventricle
...
blood flows in
...
blood flows in
...
blood flows out
...
blood flows out
...
blood flows in
...
blood flows in
...
blood flows out
...
blood flows out
...
blood flows out
...
blood flows out
...
blood flows out
...
pulmonary semilunar valve
...
tricuspid valve
...
left ventricle
...
left atrium
...
right ventricle
...
right atrium
...
pulmonary semilunar valve
...
tricuspid valve
...
aortic semilunar valve
...
mitral valve
...
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