Unit 4 Flashcards
What are cells?
The smallest units in which independent life can exist. All living things are single cells or organisms made of cells
Enzyme
A number of working proteins that speed up a specific chemical reaction, such as breaking the bonds of a nutrient, without undergoing change themselves.
Fat cells
cells that specialize in the storage of fat and form the fat tissue. Fat cells also product enzymes that metabolize fat and hormones involved in appetite and energy balance.
Nutritional genomics
The science of how nutrients affect the activities of genes and how genes affect the activities of nutrients. (also called molecular nutrition or nutrigenomics)
Tissues
Systems of cells working together to perform specialized tasks. (ex: Muscles, nerves, blood, bone)
Organs
Structural units made of tissues that perform specific jobs.
Body system
a group of related organs that work together to perform a function. (ex: Circulatory system, respiratory system)
Blood
the fluid of the cariovascular system; composed of water, red and white blood cells, other formed particles, nutrients, oxygen, and other constituents.
Lymph
the fluid that moves from the bloodstream into tissue spaces and then travels in its own vessels, which eventualy drain back into the bloodstream.
Arteries:
Blood vessels that carry blood containing fresh oxygen supplies from the heart to the tissues
Veins
blood vessels that carry blood, with carbon dioxide it has collected, from the tissues back to the heart
capillaries
weblike blood vessels that connect arteries to veins and permit transfer of materials between blood and tissues.
Plasma
the cell-free fluid part of blood and lymph
extracellular fluid
fluid residing outside the cells that transports materials to and from the cells.
intracellular fluid
Fluid residing inside the cells that provides the medium for celluar reactions
Lungs
The bodys organs of gas exchange. blood circulating through the lungs releases its CO2 and picks up fresh O2 to carry to the tissues.
Where does blood carry nutrients from?
From the intestine to the liver, which releases them to the heart, which pumps them to the waiting body tissues.
Intestine
The body’s tubular organ of digestion and the site of nutrient absorption
Liver
a Large lobed organ that lies just under the ribs.
It filters blood
-removes and processes nutrients
-manufactures materials for export to other parts of the body -destroys toxins or stores them to keep them out of circulation
- excretes fat-soluble waste products into the small intestine.
Kidneys
A pair of organs that filters waste from the blood, make urine, and release it to the bladder for excretion from the body.
Importance of blood and lymph
- delivers nutrients to all the body’s cells and carry waste materials away from them
- Blood delivers oxygen to cells
Importance of the cardiovascular system
ensures that fluids circulate properly among all organs
Hormones
Chemicals that are secreted and released by glands into the blood stream in response to conditions in the body that require regulation. These chemicals serve as messengers, acting on other organs to maintain constant conditions
pancreas
An organ with two main functions:
- Endocrine function: Makes hormones such as insulin which releases directly into the blood.
- exocrine function: Making of digestive enzymes, which it releases through a duct into the small intestine to assist in digestion.
Insulin
A Hormone from the pancreas that helps glucose enter cells from the blood
glucagon
a hormone from the pancreas that stimulates the liver to release glucose into the bloodstream with blood glucose concentration dips
What do glands secrete
Hormones that act as messengers to help regulate body processes
Cortex
the outer most layer of something. The brains cortex is the part of the brain where conscious thought takes place.H
Hypothalamus
The part of the brain that senses a variety of conditions in the blood, such as temperature, glucose content, salt content, and others.
It signals other parts of the brain of body to adjust those conditions when necessary
Fight or flight reaction
The body’s instinctive hormone and nerve mediated reaction to danger.
neurotransmitters
chemicals that are released at the end of a nerve cell when a nerve impulse arrives there. They diffuse across the gap to the next cell and alter the membrane of that second cell to either inhibit or excite it.
epinephrine
The major hormone that elicits the stress response
norepinephrine
a compound related to epinephrine that helps elicit the stress response
metabolism
the sum of all physical and chemicals changes taking place in living cells. Includes all reactions by which the body obtains and spends the energy from food.
What do the nervous system and hormonal system join to do?
Regulate body processes through communication among all the organs. They collectively respond to the need for food, the act of eating, regulate digestion, and call for the stress response.
Mircobes
Bacteria, viruses, and other organisms invisible to the naked eye, some of which cause diseases
Antigen
a microbe or substance that is foreign to the body
immune system
a system of tissues and organs that defend the body against antigens, foreign materials that have penetrated the skin of body linings
Lymphocytes
White blood cells that participate in the immune response (B cells and T cells)
phagocytes
White blood cells that can ingest and destroy antigens.
phagocytosis
the process by which a phagocyte engulfs materials.
T Cells
lymphocytes that attack antigens. T stands for the thymus gland of the neck, where the T cells are stored and matured
B cells
Lymphocytes that produce antibodies. B stands for bursa
antibodies
Proteins, made by cells of the immune system, that are expressly designed to combine with and inactivate specific antigens
Grehlin
A hormone secreted by the stomach that is thought to be the hunger hormone
Is the preference from sweet, salty, and fatty tastes natural?
Yes. It is inborn and can lead to overconsumption of foods that offer them
Digestive System
The body system composed of organs taht break down complex food particles into smaller, absorable products.
Digest
To break molecules into smaller molecules; a main function of the digestive tract with respect to food.
Absorb
To take in, as nutrients are taken into the intestinal cells after digestion; the main function of the digestive tract with respect to nutrients.
Peristasis
Moves the digestive tract contents
Segmentation
Alternating forward and backward movement allowing for greater contact between the partially digested food and intestinal juices and enzymes, thus resulting in virtually complete digestion of the food we eat.
Stomach
A muscular, elastic, pouchlike organ of the digestive tract that grinds and churns swallowed food and mixes it with acid and enzymes, forming chyme
sphincter
a circular muscle surrounding, and able to close, a body opening
chyme
a fluid composed of chewed food particles and digestive enzymes. it ensures that the food undergoing digestion is in a form that allows digestive chemicals to work effectively.
pyloric valve
the circular muscle of the lower stomach that regulates the flow of partly digested food into the small intestine
small intestine
7 metre in length. It is the small diameter intestine below the stomach and above the large intestine.
It is the major site of digestion of food and the absorption of nutrients
The large intestine (The Colon)
The portion of the intestine that complete the absorption process
Feces
the waste material remaining after digestion and absorption are complete
Mechanical Digestion
The processes within the digestive system that moves through throughout its varies chambers by mechanical means. ex: chewing, mixing by the stomach, and peristalsis.
Chemical Digestion
The processes by which the digestive system chemically breaks down and, allows for the absorption of, the nutrients within the food we ingest. (ex: SALIVA, gastric juice, etc)
Gastric Juice
the digestive secretion of the stomach
pH
the measure of acidity on a point scale. 1 is strong acid, 7 is neutral, and 14 is strong base.
Muscus
The coating of the digestive tract lining that protects the cells from exposure to digestive juices.
Why is the small intestine considered the organ where the digestive process really begins
it finishes what the mouth and stomach have already started.
- Hormonal messengers signal the gallbladder to contract and release the right amount of bile into the intestine
- Other hormones notify the pancreas to release pancreatic juice (containing bicarbonate) that neutralizes the stomach acid in the lower intestine
Emulsifier
a compound with both water soluble and fat-soluble portions that can attract fats and oils into water, combining them.
Villi
Fingerlike projections of the sheets of cells that line the intestinal tract. Villi make the surface area much greater than it would otherwise be
Mircovilli
Tiny hairlike projections on each cell of every villus that greatly expand the surface area available to trap nutrient particles and absorb them into the cells.
Ulcer
erosion in the topmost layers of cells that form a lining
gastroesophageal reflux disease
Called GERD
Chronic splashing of stomach acid and enzymes into the esophagus, throat, mouth, or airway that causes inflammation and injury to those organs.
duodenum
The first part of the small intestine where food is actioned on by bile and pancreatic juices
jejunum
First two fifths of the small intestine beyond the duodenum. Principal function is the absorption of digested material
ileum
Last segment of the small intestine that precedes the large intestine and functions in the absorption of nutrients
Bolus
The peristaltic waves that pass food along the digestive tract
segmentation
the periodic squeezing of the circular muscles in the segments of the intestine.
monosaccharide
single sugar molecule
disaccharide
pair of monosaccharides linked together
polysaccharide
numerous monosaccharides linked together
disacchraDISE
The enzyme involved in hydrolyzing a specific disaccharide into its monosaccharide components
dipeptide
two amino acids bonded together
tripeptide
three amino acids bonded together
polypeptide
10 or more amino acids bonded together. These form proteins
fatty acid
the building blocks of fat
glycerol
the backbone to which fatty acids are attached to produce a glyceride
monoglyceride
a molecule of glycerol with one fatty acid attached
diglyceride
a molecule of glycerol with two fatty acids attached
triglyceride
a molecule of glycerol with three fatty acids attached. This is the predominant form of fat in the body
emulsified fat
fat droplets dispersed and stabilized in a watery solution with the help of emulsifiers
lipase
breaks down emulsified fat into monoglycerides, free fatty acids, and glycerol
amylase
Breaks down starch and polysaccharides into maltose. Its in the mouth
Hydrochloric acid
produced in stomach. it creates optimal conditions for the enzyme pepsin to work. Pepsin breaks proteins down into smaller peptides.
Hydrochloric acid also kills’ most bacteria that enters the body along with the food.
pH of 2
Absorption
The passage of simple nutrients through the epithelial cells of the small intestine and into the blood stream or the lymphatic system
chylomicron
Fatty acids with long hydrocarbon changes and fat soulbe vitamins that cannot gain access into the capillaries. They cluster together in the intestinal cells to form large fat molecules which special protein carriers are attached.
