Unit 1 Flashcards
Physiology
The study of the normal functioning of a living organism and its component parts.
Homeostasis
The maintenance of a relatively stable internal environment via automatic control mechanisms (maintains a similar condition for all cells of the body). A central organizing principle of physiology.
Acclimatization
Environmentally induced change in physiological function with no genetic change (short-term change) ex. acclimatization to altitude OR temperature change.
Local Control
The effects are exerted on neighbouring cells (paracrine and autocrine response).
Cell Membrane
The layer that separates the cell from the external environment.
Receptor
A protein where a signal (ligand) binds to cause a change in that cell.
Gap Junctions
Allows molecules to pass through cells and the transfer of information (communication) via protein channels (connexons). Capable of opening and closing.
Anchoring Junctions
Joins cells together or to the extracellular matrix.
Connective Tissue
Provides structural support and barriers. Between organs to keep them in place. Has an extensive extracellular matrix (ECM) that contains proteoglycans, collagen, elastin, and fibronectin.
Neural Tissue
Carries information from one part of the body to another. There is very little ECM in neural tissue.
Autocrine
When chemicals act on the cell that produced them (the cell signals itself).
Contact-Dependent Communication
The interaction between membrane molecules on two cells (direct contact).
Neurohormone
Any of a group of substances that are produced by specialized neurosecretory cells of the nervous system and that are released into the blood, similar to hormones of the endocrine system.
Hormone
Chemical signals used in the endocrine system.
Agonist
A ligand that can bind to the same receptor as the primary ligand and cause the same response.
Specificity
Only certain ligands can bind to certain receptors (lock and key mechanism).
Organ Systems
When different organs work together perform a particular function.
Setpoint
The baseline levels (when homeostasis is achieved).
Reflex Control
Long-distance response. The reaction in one or more organs controlled from elsewhere in the body (can be any long-distance path of the nervous and/or endocrine system).
Positive Feedback
Response sends a signal (reinforces stimulus sending the variable further from the set point until an external signal turns the response off) ex. labour. Is not homeostatic (response reinforces the stimulus).
Negative Feedback
Results in a change that opposes or removes the stimulus (allows for homeostasis) ex. blood pressure.
Feedforward Control
Anticipatory control (predicts that change is about to happen and starts the response loop (prevents change)) ex. sight, smell, or thought of food.
Tight Junctions
Prevents movement of molecules between cells. Helps with control and regulation.
Epithelial
Protects the internal environment of the individual. Regulates exchange of material between the external environment and internal environment (any material that moves between these two environments must cross an epithelium). Consists of one or more layers of cells connected to one another and to a basal lamina (basement membrane).
