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).
Muscle
Has the ability to produce force and movement.
Paracrine
When chemicals secreted by a cell act on neighbouring cells.
Endocrine
Long distance signalling via hormones and blood (used in the endocrine system).
Long-Distance Communication
Signals travel long distances (nervous and endocrine systems).
Neurotransmitter
Any of a group of chemical agents released by neurons (nerve cells) to stimulate neighbouring neurons or muscle or gland cells, thus allowing impulses to be passed from one cell to the next throughout the nervous system.
Primary Ligand
The main ligand for the receptor.
Antagonist
Prevents the response, competing with the primary ligand (competitive inhibitor).
Response
What the cell does in response to the signal.
Levels of Organization
1) Chemical
2) Cellular
3) Tissue
4) Organ
5) Organ System
6) Organism
7) Community/Ecosystem/Biosphere (Ecology focus, not seen in Physiology)
Tissue Types
1) Epithelial
2) Connective
3) Muscle
4) Neural
Integrative Approach
Look at physiology in a hollistic approach (how everything works together to function as a unit). Attempting to understand how events within a single cell influence neighbouring cells, tissues, organs, and organ systems.
Function
The why (why does the system exist?).
Mechanism
The how (how does the system work?).
Cell-to-Cell Communication Types
1) Gap Junctions
2) Contact-Dependent Signals
3) Local Communication
4) Long-Distance Communication
Chemical Messengers
Ligands. Send signals throughout the body.
Control
The body regulates itself so that homeostasis is achieved.
Key Concepts/Themes in Physiology
1) Structure and Function Relationships
2) Biological Energy
3) Information Flow
4) Homeostasis
Types of Anchoring Junctions
1) Adherens
2) Desmosomes
3) Hemidesmosomes
Apical Membrane
Facing the extracellular fluid.
Basal/Basement Membrane
Outside facing membrane towards the basal lamina.
Extracellular Matrix (ECM)
Between cells and is synthesized and secreted by cells in the tissue.
Types of Epithelia
1) Exchange
2) Ciliated
3) Secretory
4) Transporting
5) Protective
Exchange Epithelia
Rapid exchange of material (usually gas exchange ex. lungs).
Ciliated Epithelia
Lines airways and female reproductive tract (hair-like functions that “sweep”).
Secretory Epithelia
Synthesize and release products into the external environment/blood (mucus membranes).
Transporting Epithelia
Selective transport of material (non-gas exchange).
Protective Epithelia
Found on surface of the body ex. skin.
Squamous Epithelium
Flat, thin cells. Used for gas exchange.
Cuboidal Epithelium
Cube shaped cells. Lines the ducts and glands.
Columnar Epithelium
Column shaped cells. Lines the digestive tract and airways.
Types of Connective Tissue
1) Loose
2) Dense
3) Adipose
4) Blood
5) Supporting
Loose Connective Tissue
Elastic tissue ex. tissue underlying the skin.
Dense Connective Tissue
Primary function is strength ex. tendons.
Adipose
Fat. Contains adipocytes (fat cells).
Types of Fat
1) White Fat
2) Brown Fat
White Fat
Used for storage.
Brown Fat
“Better” fat, helps generate heat.
Blood
Watery matrix lacking insoluble protein fibers.
Supporting Connective Tissue
Dense substances ex. cartilage and bone.
Types of Muscle
1) Skeletal
2) Smooth
3) Cardiac
Skeletal Muscle
Responsible for gross (large) body movement.
Smooth Muscle
Responsible for influencing the movement of substances into/out of/within the body.
Cardiac Muscle
Found only in the heart, contraction moves blood through the body.
Types of Neural Tissue
1) Neurons
2) Glial Cells
Neurons
Carry information as electrical or chemical signals.
Glial Cells
Supporting cells for neurons.
The Major Organ Systems
1) Nervous System
2) Musculoskeletal System
3) Circulatory System
4) Respiratory System
5) Immune System
6) Endocrine System
7) Reproductive System
8) Digestive System
9) Urinary System
10) Integumentary System (Skin)
Connexons
Protein channels between gap junctions.
Local Communication
Communication with neighbouring cells (paracrine and autocrine).
Signalling Steps
1) Activation of Receptor
2) Signal Transduction
3) Response
4) Termination
Response Pathway
1) Stimulus
2) Sensor
3) Input/Afferent Signal
4) Integrating Center
5) Output/Efferent Signal
6) Target/Effector
7) Response
Stability
Result of balance between input and output.
Response Loops
Start with a stimulus and result in a response.
Simple Tissue
One cell layer thick.
Stratified Tissue
Multiple cell layers thick.
Histamine
An example of a paracrine signalling molecule (a vasodilator).
3 Domains of Membrane Spanning Proteins
1) Extracellular (binds to ligand, chemical signal).
2) Trans-membrane (hydrophobic).
3) Intracellular (cytoplasmic) - activates the cellular response.
Types of Receptors
1) Receptor-Channel
2) G Protein-Coupled Receptor
3) Catalytic Receptors
—> Receptor-Enzyme
—> Integrin Receptor
Receptor-Channel
Ligand binding opens or closes the channel.
G Protein-Coupled Receptor
Ligand binding to a G protein-coupled receptor opens an ion channel or alters enzyme activity.
Receptor-Enzyme
Ligand binding to a receptor-enzyme activates an intracellular enzyme.
Integrin Receptor
Ligand binding to integrin receptors alters enzymes or the cytoskeleton.
