Midterm Review 1/3 Flashcards
True/False: Most of the human body is fluid.
True
How much of the human body is fluid?
50-70%
How much of the fluid in the body is intracellular?
2/3
How much of the fluid in the body is extracellular?
1/3
Which is more abundant: intracellular fluid or extracellular fluid?
Intracellular
What did Claude Bernard call the internal environment of the body?
milieu interieur
What is contained in the extracellular fluid
electrolytes, nutrients, sodium, chloride, bicarbonate, oxygen, glucose, fatty acids, amino acids, CO2
What is contained in intracellular fluid?
Potassium, magnesium, phosphate
What is the definition of homeostasis?
Maintenance of nearly constant conditions in the internal environment
Who coined the term homeostasis?
Walter Cannon
What are the three examples of the body maintaining homestasis?
- Lungs supply constant source of oxygen
- GI tract supplies nutrients
- Kidneys maintain ion concentration
Disease is a state of ____.
disrupted homestasis
In extracellular fluid, where does the blood move?
through blood vessels
Where does fluid move in extracellular fluid?
between capillaries and cells
What allows basic diffusion to occur in the extracellular fluid?
Continual exchange of ECF between plasma in blood and interstitial fluid between cells
Are capillaries permeable?
yes
What is not permeable through capillaries?
large plasma proteins
How is oncotic pressure maintained?
The capillary holds onto large plasma protein because the protein has a negative charge and holds fluid in the blood vessels
True/False: Most cells are located more than 50 micrometers from a capillary.
False; Few cells are located more than 50 micrometers from a capillary
What is the definition of the cell?
basic living unit of the body
What are the two main components that occupy the cell?
Nucleus and Cytoplasm
How is the cytoplasm separated from the nucleus?
by a nuclear membrane
How is the cytoplasm separated from fluid?
by the cell membrane
How much water is the cell composed of?
70-85%
What are examples of ions contained in the cell?
potassium, magnesium, phosphate, bicarbonate, sodium, chloride, calcium
What is the function of ions in the cell and give an example?
provide chemicals for cellular reactions (e.g. ions at cell membrane are needed to transmit impulses in nerve and muscle fibers)
How much of the cell is made of protein?
10-20%
What functions do proteins have in the cell?
structure and enzymes that catalyze reactions
What are structural proteins?
long thin filaments provide contraction, cytoskeleton
Where are functional proteins found?
often adhere to inside cell membrane
What percent of the cell is fat?
2%
True/False: We need a certain amount of fat in our diet
True
True/False: We need a certain amount of cholesterol in our diet.
True
Where are lipids found in the cell?
Insoluble in water so it forms the cell membrane and intracellular membrane barriers
What are lipids broken down into?
Phospholipids
Cholesterol
Triglycerides (in fat cells/adipocytes) for energy stores
What are adipocytes?
fat cells
What is the function of carbohydrates?
energy
What are carbohydrates broken down into?
glucose
What is the function of glucose in dissolved in extracellular fluid?
readily available energy to the cell
What is the function of intracellular glycogen?
backup system stored in the cell that can be used rapidly if needed
What is the cell membrane?
Water-insoluble barrier made of lipids and protein
Where is the cell membrane found?
Covering the cell and internal organelles such as mitochondria, nucleus, endoplasmic reticulum
What is the function of the cell membrane?
Keeps the cell intact, prevents water penetration, and acts as a gatekeeper (Protein molecules form pores through membrane for passage of specific substances)
What are the two types of phospholipids that are in the cell membrane?
Hydrophilic and Hydrophobic
Where are the hydrophilic ends of the cell membrane?
cover outside in contact with water
Where are the hydrophobic ends of the cell membrane?
in center (soluble only in fats)
What can penetrate the hydrophobic ends?
fat-soluble substances such as oxygen, CO2 and alcohol
What is the function of proteins ON the cell membrane?
- Provide pores to allow water and water-soluble
substances through cell membrane (e.g. ions) - Acts as Carrier proteins to transport substances
that could not penetrate lipid bilayer, also provide
active transport - Serve as Receptors for water-soluble chemicals
such as peptide hormones
What is the function of carrier proteins?
to transport substances
that could not penetrate lipid bilayer, also provide
active transport
Where are peripheral proteins found un the cell?
Attached to the inside of the cell membrane
