Download Biology Mid-Term Study Guide 8: Nutrition Food and Energy Energy

Biology Mid-Term Study Guide 8: Nutrition
I.
II.
Food and Energy
a. Energy in food can be measured by burning the food
b. A Calorie is the amount of energy in food
c. Calorie=1000 calories
Nutrients
a. Substances in food that supply energy and raw materials your body uses for
growth, repair, and maintenance
b. Nutrients needed by the body are water, carbohydrates, fats, proteins, vitamins,
and minerals
c. Water
i. Most important nutrient
ii. Every cell in the human body needs water because many of the body’s
processes including chemical reactions take place in water
iii. Water makes up the bulk of blood, lymph, and other bodily fluids
iv. Sweat glands remove water from body tissue
v. One liter of water needed per day
d. Carbohydrates
i. Main source of body’s energy
ii. Sugars found in fruits, honey, and sugar cane
1. Monosaccharides
iii. Starches found in potatoes, grains, and vegetables are complex
carbohydrates
1. Polysaccharides
2. Broken down in the digestive system into simple sugars
3. Absorbed into the blood stream
4. Carried to cells throughout the body
iv. Sugars not used for energy are converted to complex carbohydrate
glycogen
1. Stored in liver and skeletal muscles
v. Fiber or cellulose is needed for diet
1. Body cannot breakdown cellulose
e. Fats
i. Important to a healthy diet
ii. Formed from fatty acids and glycerol
iii. Body cannot manufacture all needed fatty acids
iv. Essential fatty acids found in vegetable oils
v. Fats are used to produce cell membranes, myelin sheaths, and certain
hormones
vi. Saturated Fats
III.
IV.
1. Maximum number of hydrogen atoms
vii. Unsaturated Fats
1. At least one double bond in a fatty acid chain
2. Normally liquid
f. Proteins
i. Supplies raw materials for growth and repair of structures such as skin and
muscle
ii. Polymers of amino acids
g. Vitamins
i. Organic molecules that regulate body processes
ii. Obtained from food or produced by bacteria
h. Minerals
i. Inorganic nutrients the body needs in normally small amounts
ii. Calcium
iii. Iron
iv. Magnesium
The Mouth
a. The function of each organ of the digestive system is to help convert foods into
simpler molecules
b. Teeth
i. Anchored by jaw bone
ii. Teeth protected by enamel
iii. Mechanical Digestion
1. Physical Breakdown of food
c. Saliva
i. Salivary glands secret saliva
ii. Moisten food
iii. Contains amylase (enzyme)
iv. Works with teeth to break down foods
v. Chemical Digestion
1. Chemical breakdown
The Esophagus
a. Epiglottis prevents food from clogging air passageways
b. Bolus (Ball of food) passes through esophagus
c. Smooth muscles that move food through it
i. Peristalsis
d. Think ring of muscle called the cardiac sphincter closes after food passes through
into the stomach to prevent contents from moving back up
e. Heartburn
i. Caused by stomach juices and acids splashing on the esophagus
V.
VI.
VII.
VIII.
The Stomach
a. Continues mechanical digestion of food
i. Muscles that contract and expand
b. Chemical Digestion
i. Lining on stomach continues chemical digestion
ii. Glands produce hydrochloric acids that activate pepsin (enzyme)
c. Ulcers
i. Powerful acids released into the stomach sometimes damaging the organ’s
own lining
ii. Produces a hole called a peptic ulcer
d. Mechanical digestion
i. Muscles contract to churn and mix stomach fluids with food
ii. Produces chyme
iii. After an hour of two the pyloric valve will open and chyme flows to
intestines
Pancreas and Liver
a. Duodenum is the first part of the small intestine to get the chyme
b. Small intestine is where most of the chemical digestion occurs
c. Chyme mixes with enzymes and digestive fluids in the duodenum
d. Pancreas glands
i. Produce hormones that regulate blood sugar levels
ii. Produces enzymes that breakdown carbohydrates, proteins, lipids, and
nucleic acids
e. Liver
i. Assist Pancreas
ii. Produces bile
iii. Acts like detergent
1. Dissolves and disperses the droplets of fat found in fatty foods
2. Bile is stored in gall bladder
The Small Intestine
a. Chemical digestion is mostly completed by the time chyme reaches the jejunum
and ileum
b. Covered by villi
c. Carbohydrates moved to the capillaries in villi
Large Intestine
a. Complex organic molecules have been digested and absorbed
b. Chyme enters large intestine or colon
c. Remove water from undigested material
d. Appendix above
i. Appendicitis (Inflamed appendix)
IX.
X.
e. Water moved across large intestine
f. Bacteria digests undigested foods
Excretory System
a. Excretion
i. Skin excretes water and salts
ii. Skin also excretes small amounts of urea
1. Toxic compound that is produced when amino acids are used for
energy
iii. Lungs excrete carbon dioxide
iv. Skin, lungs, and kidneys, make up the excretory system
The Kidneys
a. Located on either side of the spinal column
b. Tube called ureter leaves kidney carrying urine to urinary bladder
c. Waster-laden blood enters the kidney through the renal artery
d. Kidney Structure
i. Inner part called renal medulla
ii. Outer is renal cortex
1. Nephrons are in the renal cortex
a. Each has its own blood supply
i. An arteriole, a venule, and network of capillaries
b. Blood enters nephron through arteriole
c. Blood passes through the capillaries and filtered
d. Waste removed
e. Blood ends up in the collecting duct
i. Leads to ureter
e. Filtration
i. Blood flows into the glomerulus
1. Small network of capillaries encased by upper end of neuron called
Bowman’s capsule
ii. Blood is under pressure and walls of the capillaries and bowmen’s
capsule are permeable
1. Fluids flow from blood into capsule
a. Filtration
f. Reabsorption and Secretion
i. Material removed from blood makes its way back to blood by
Reabsorption
ii. Nutrients such as amino acids are removed from filtrate by active transport
and reabsorbed by capillaries
iii. Loop of Henle
1. Water is conserved and urine volume is minimized
XI.
XII.
iv. Urine is stored in urinary bladder until it can be released from that body in
a tube called the urethra
Control of Kidney Function
a. Kidneys play an important role in maintaining homeostasis
b. They regulate the water content of the blood and therefore blood volume,
maintain blood pH, and remove waste products from the blood
c. Kidneys controlled by composition of blood
d. Kidneys prevent body swelling by controlling concentration of water and
absorbing water
Homeostasis by Machine
a. Transplant kidneys
i. Alternative if both kidneys are damaged
ii. Kidney dialysis machine is other alternative