Nutrition Unit 2 Flashcards
Body Cells (Definition)
The smallest unit in which independent life can exist. Need energy, oxygen, and nutrients to remain healthy and do work.
Regulators in the Body
- Genes
- Proteins
- Co-enzymes
Genes
- Units of a cell’s inheritance that act as a code or recipe
for the making of protein to do the body’s work. Proteins
of a cell determine a cell’s structure and the functions it
can perform. - Genes are segments of a cell’s DNA (deoxcyribomucleic
acid). Chromosomes are composed of the DNA and
protein. - Each cell contains all genes but different ones are active
in different cells.
Proteins
- Enzyme: Facilitates/speeds up a chemical reaction
without itself being altered in the process. Many in the
body. - Hormones: Chemical messengers that control the
activity of other organs. Produced by glands (specialized
cells).
Co-Enzymes
- Non-Protein, organic molecule that works with the
enzyme to promote the enzyme’s activity (aids the
action of the enzyme). - Many have B vitamins as part of their structure.
Organization of the Body
Cells-Tissue- Organs- Systems- Whole Body
Body Fluids and the Cardiovascular System
- Blood
- Extracellular Fluid
- Intracellular Fluid
- Lymph
Blood
- Fluid of the cardiovascular system composed of water,
red and white blood cells, platelets, nutrients, oxygen
and other constituents. - Blood travels in:
Arteries: Blood vessels that carry oxygen from the heart to the tissues.
Veins: Blood vessels that carry CO2 and other wastes from the tissues back to the heart.
Capillaries: Minute, weblike blood vessels that connect arteries to veins and permit transfer of materials (CO2, O2, nutrients, and fluid) between blood and tissues.
Extracellular Fluid
- Fluid outside the cells that bathes the cells and
transports materials to and from the cells.
Intracellular Fluid
- Fluid within the cell that provides the medium for cellular reactions and helps the cell to hold its shape.
Lymph (Fluid)
- Excess tissue fluid not reabsorbed by blood capillaries.
- Lymphatic capillaries take up excess tissue fluid and
return it to the blood stream.
Cardiovascular System
- Organ system composed of the heart and blood
vessels. Its function is to transport nutrient-rich,
oxygenated blood to the tissues and pick up CO2 and
other waste products, carrying them to points of
disposal. - Blood Flow Diagram (see page 75 of text):
Lungs: O2 picked up by the blood, CO2 released. Blood returns to the heart and is pumped to other parts of the body.
Liver: Filters toxins from the blood and accepts blood from the digestive system, altering the absorbed materials to make them better suited for use by other tissues (“Gatekeeper of the blood). Blood then returns to the heart.
Intestines: After food is broken down in the intestines, nutrients are picked up by the blood vessels in the intestines and transported to the liver. Large fats picked up by intestinal lymphatic vessels which then transport them to the blood.
Kidneys: Cleanses the blood of wastes. Blood then returns to the heart.
Lungs
O2 picked up by the blood, CO2 released. Blood returns to the heart and is pumped to other parts of the body.
Liver
Filters toxins from the blood and accepts blood from the digestive system, altering the absorbed materials to make them better suited for use by other tissues (“Gatekeeper of the blood). Blood then returns to the heart.
Intestines
After food is broken down in the intestines, nutrients are picked up by the blood vessels in the intestines and transported to the liver. Large fats picked up by intestinal lymphatic vessels which then transport them to the blood.
Kidneys
Cleanses the blood of wastes. Blood then returns to the heart.
The Hormonal (Endocrine) System, Nervous System, and Hunger Relations
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Homeostasis
The relatively constant, self-correcting internal environment of a living organism.
To maintain homeostasis, cells in the body must communicate with each other.
Each cell communicates with its neighbor or by releasing chemicals into the extracellular fluid.
Communication over long distances, however, is coordinated by the endocrine and nervous systems.
The nervous system joins the hormonal system to regulate body processes through communication among all organs.
Hormonal (Endocrine System)
- System of cells, tissues, and organs used for life
processes (growth, development, reproduction,
regulation) that require long-term (leisurely)
communication. - Uses hormones as the chemical messengers.
Examples:
Pancreas- monitors blood sugar levels. If blood sugar is high, insulin is released which helps glucose to enter cells. If blood sugar is low, glucagon is released which stimulates the liver to release its stored glucose into the bloodstream. Insulin and glucagon are examples of hormones.
Nervous System
- Organ System consisting of the brain, spinal cord, and
nerves that coordinate the other organ systems of the
body. The nervous system is our rapid method of
communication. - Uses neurotransmitters as the chemical messengers.
Hunger Regulation ( a joint effort by the hormonal and nervous systems)
- The sensation of hunger and fullness are perceived by
the cortex, the brain’s thinking, outer layer. We have the
ability to override these signals and choose not to eat
or ignore that we are full. - Deep inside the brain is the hypothalamus which
monitors many body conditions (including the availability
of nutrients) and communicates with the cortex and
other parts of the body. - Internal signals come to the hypothalamus from the
digestive tract by way of hormones and the nervous
system. Fat tissue produces a hormone that informs the
brain about the degree of body fatness that helps to
regulate appetite. The sight and smell of food can also
increase or decrease appetite.
Immune System
- Enables the body to resist diseases.
- Protects the body against antigens: foreign substances
that stimulate the immune system. Antigens can be a
pathogen (bacterium, virus), part of a foreign cell, toxin
or cancer cell.
Parts of the Immune System
- Barrier to Entry
- White Blood Cells
- Lymphoid Organs
Barriers to Entry
- Skin and mucous membranes lining the respiratory,
digestive, and urinary tracts.
-Oil glands on the skin- chemicals weaken or kill bacteria. - Hydrochloric Acid in the stomach inhibits/ kills bacteria.
- Helpful bacteria in the intestines inhibit growth of
pathogens (disease-causing agents).
