Homeostasis and Cell Structure 1 Flashcards
Homeostasis
Homeostasis refers to all organs and tissues in the body perform a function to maintain relatively constant conditions.
Physiological systems regulate via what?
Adaptive responses
Intracellular fluid compartments
located within the cell. Contains all cell machinery. Heavy in Potassium, magnesium, and phosphate ions
Extracellular fluid compartments
located outside the cell and is open to the blood stream. The fluid continuously circulates throughout the body. The fluid contains ions and nutrients required for cell function. Contains sodium, chloride, bicarbonate ions, oxygen, glucose, fatty acids, carbon dioxide, and amino acids.
Positive feedback loops
b. Positive feedback is often a snowball effect. It continuously increases until it is fully out of control or has a natural end, like using up all of the reactants/fuel.
Negative feedback loops.
Negative feedback often increases a value or concentration of a substance which, upon reaching a certain level will act upon a previous mechanism to stop the effect of increasing a value or concentration.
Examples of negative feedback loop
Regulation of Arterial blood pressure. High blood pressure -> pressure increase on artery walls -> Walls send neural impulses to the medulla -> Medulla signals the heart to slow the pumping -> blood pressure falls.
Examples of positive feedback loop
in childbirth, the stretching of the cervix causes more contraction, which causes more stretching of the cervix. Childbirth does have a natural end. (baby flies out)
Explain how the molecular structure of the cell membrane influences the passage of materials through the cell membrane
The membrane is semi-permeable and only allows the passage of certain fatty-acids. In addition the embedded proteins are often channels that allow for passage of other substances like water.
Describe the universal structure of cellular membranes
All membranes make up of mostly a phospholipid bilayer composed of Phospholipids, sphingolipids, Proteins (most abundant), and cholesterol.
Function of Endoplasmic Reticulum
helps process molecules synthesized within the cell and assists in transporting them to destinations inside and outside the cell. Is bout by a membrane. Encompasses the nucleus. Provide functions for internal mechanisms. b. Ribosomes - some attach to the ER for synthesis. A mixture or RNA and protein and used to synthesize more complex protein.
Function of Ribosomes
some attach to the ER for synthesis. A mixture or RNA and protein and used to synthesize more complex protein.
Golgi Apparatus
Composed of 4 or more layers of stacked membrane. Used for transportation and modification of molecules outside of the cell, aka, secretory. Provides the Transport Vesicles. Makes lysosomes.
Lysosomes
composed of lipid bilayer. Used as an intercellular digestive system that destroys damaged cellular structures, food, or unwanted material. Typically requires more than one. Contains hydrolytic enzymes within.
Peroxisomes
similar to lysosomes, have a membrane but contain oxidases which are capable of forming hydrogen peroxide. Allows for a major detoxification function to occur.
