(Lectures 1-3) Intro Flashcards
1
Q
Physiology
A
Study of an organism’s functions
2
Q
Levels of organization in the body (6)
A
Chemical < Cellular < Tissue < Organ < System < Organismal
3
Q
Components of chemical level
A
Atoms, molecules
4
Q
Examples of elements essential to maintaining life
A
Carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, sulfur
5
Q
Def. of cell
A
- Basic structural/functional units of an organism
- Smallest unit capable of supporting life
6
Q
6 life processes
A
- Metabolism
- Reproduction
- Differentiation
- Growth
- Movement
- Responsiveness
7
Q
Metabolism
A
Sum of all reactions in the body; catabolism (breakdown) + anabolism (synthesis)
8
Q
Responsiveness
A
Body’s ability to detect and respond to internal/external environmental changes
9
Q
Movement
A
Motion of the body, organs, cells, and intercellular structures
10
Q
Growth
A
Increase in body size due to
- An increase in the number of cells
- An increase in the size of existing cells
- An increase in material between cells
11
Q
Differentiation
A
Development of a cell from an unspecialized to a specialized state
12
Q
Reproduction
A
Formation of new cells for tissue growth/repair/replacement, or the production of a new individual
13
Q
What is homeostasis?
A
The maintenance of relatively stable conditions in the body’s internal environment despite changes to the external environment
It’s dynamic, and maintained by the processes that control and regulate the body.
14
Q
T/F: Homeostasis in the body is only maintained at the cellular level
A
False; it’s maintained at all levels
15
Q
Compartmentalization
A
- Body is divided into compartments that contain fluids and are separated by semipermeable membranes
- Transport occurs between the compartments
- Exchange between internal/external environments helps maintain homeostasis
16
Q
Feedback Loop
A
A cycle of events where a parameter of the internal environment is repeatedly monitored, evaluated, and changed
17
Q
Feedforward
A
Mechanism used by our bodies in anticipation of a change in a controlled variable (e.g. mouth watering in anticipation of food)
18
Q
T/F: homeostasis is fixed at a certain point
A
False
19
Q
Homeostatic set point
A
Value around which the normal range of a variable fluctuates; serves as an error-sensing function
20
Q
T/F: there are always minor adjustments being made to maintain a normal operating range
A
True
21
Q
Negative feedback
A
Reverses a change in a controlled variable
22
Q
Positive feedback
A
Strengthen/reinforce a change in a controlled variable
23
Q
Stimulus
A
Disrupts homeostasis by either increasing or decreasing a controlled variable
24
Q
Receptors
A
Sense changes to controlled variables and send input (action potentials) to the control center
25
Control center
- Determines the set point
- Evaluates input from receptors
- Generates output when necessary
26
Effectors
Receive output from the control center, produce a response that changes the controlled variable
27
3 main components of a cell
- Plasma membrane (outer surface)
- Cytoplasm (cellular contents between membrane and nucleus)
- Nucleus (contains most of the cell's DNA)
28
Structure of the plasma membrane
- Lipid bilayer; polar/hydrophilic heads face the ECF and cytosol, with the nonpolar/hydrophobic tails between them
- Contains phospholipids, cholesterol, glycolipids
29
Peripheral proteins
Found on the surface of the membrane (either internal or external)
30
Integral proteins
Found within the lipid bilayer; known as transmembrane proteins if they span the lipid bilayer
31
Functions of membrane proteins
- Anchoring proteins
- Recognition proteins
- Enzymes
- Receptor proteins
- Carrier proteins
- Channels
32
What is the cytosol?
Cytoplasm - organelles
- Site of many chemical reactions
- Mostly water w/many dissolved particles (ions, glucose, amino acids, etc.)
33
What are organelles?
Specialized structures in the cell with specific functions
34
Ribosomes
- Site of protein synthesis
- High rRNA content
- Each one includes ~80 proteins
35
Endoplasmic Reticulum
Network of membranes; flattened sacs, tubules
- Rough ER has ribosomes
- Smooth ER extends from rough ER; site of lipid synthesis, does not have ribosomes
36
Mitochondria
Powerhouse of the cell! Make ATP
37
Cytoskeleton - what are the 3 types?
Network of protein filaments that extends through the cytosol
- Microfilaments (thinnest)
- Intermediate filaments
- Microtubules (thickest)
38
Microfilaments
- Made of actin
- Mostly found at the edge of the cell
- Help generate movement
- Provide mechanical support
- Form microvilli
39
Intermediate Filaments
- Found where cells experience stress
- Help position organelles
- Attach cells to each other
40
Microtubules
- Hollow tubes, consist mostly of tubulin
- Determine cell shape
- Move organelles
- Found in cilia, flagella
41
4 primary types of tissue
- Nervous
- Epithelial
- Connective
- Muscle
42
Neural Tissue
- Detects/responds to changes in the body's external and internal environment
- Consists of neurons and neuroglia
43
Muscle Tissue
- Convert electrical signals into mechanical force; contract to generate movement
- Can be voluntary or involuntary
44
Epithelial Tissue
- Covers body surfaces, lines internal body surfaces/cavities
- Forms glands
- Main function is as a protective barrier
45
Connective Tissue
- Binds tissue together
- Supports/strengthens
- Protects/insulates internal organs
- Major transport system in the body
46
Cell Junctions
Specialized components in the plasma membrane that hold cells together and help form tissues.
47
Tight Junctions
- Web-like strands of transmembrane proteins that connect the outer surfaces of adjacent plasma membranes.
- Prevent substances from passing between cells
48
Desmosomes
- Form filament-like junctions between cells
- Bind cells together, providing additional strength (important where cells are under high mechanical stress!)
- Contain the transmembrane protein cadherin
49
Gap Junctions
- Form tunnels between cells so they can exchange materials (cytosol, ions, etc.); i.e. directly communicate with each other
50
Hemidesmosomes
- Anchor cells to the basement membrane
| - Contain the transmembrane protein integrin
51
Adherens Junctions
- Help epithelial surfaces resist separation during contractile movements
- Contain plaque that attaches to membrane proteins and microfilaments
- Encircle a cell, forming zones called adhesion belts
52
What substances can pass through the plasma membrane?
- Nonpolar molecules
| - Small, uncharged polar molecules
53
What substances can't passively move through the plasma membrane?
- Ions
| - Large, uncharged polar molecules
54
What features of the membrane affect permeability?
- Transmembrane proteins (carriers, channels)
- Lipids (form vesicles)
- Cholesterol (can make membrane impermeable)
55
What is a concentration gradient?
The different in concentration between two areas (e.g. either side of a plasma membrane)
56
What is an electrical gradient?
The difference in electrical charge between two areas (e.g. either side of a plasma membrane - created by ions)
57
What is an electrochemical gradient?
Electrical gradient + concentration gradient
58
Passive Transport
Substances move down their concentration/chemical gradient without the expenditure of energy
59
Active Transport
Substances move against their concentration; energy is required
60
What process is linked to other reactions so they can easily use the energy it releases?
ATP hydrolysis
61
Factors that affect diffusion
- Steepness of concentration gradient
- Temperature
- Mass of diffusing particle
- Surface area
- Diffusion distance
62
Simple diffusion
Movement of substances directly through the plasma membrane
63
Facilitated diffusion
Movement of substances through carriers/channels down their concentration gradient
64
T/F: Channels (for facilitated diffusion) are not ion-specific
False
65
Which two ion channels are more common in plasma membranes?
K+ and Cl-
66
Between simple and facilitated diffusion, which is faster?
Simple diffusion
67
Channel-mediated facilitated diffusion
Solutes move down their concentration/electrochemical gradient through a membrane channel
68
Carrier-mediated facilitated diffusion
Solutes move down their concentration/electrochemical gradient by binding to a carrier protein. A change in the protein's shape allows the solute to enter or exit the cell.
69
Osmosis
Net movement of a solvent through a selectively permeable membrane.
Occurs by simple diffusion and through aquaporins (channels)
70
Hydrostatic Pressure
Pressure exerted by a liquid
71
Osmotic Pressure
The amount of pressure needed to completely stop the osmotic movement of water
72
Osmolarity
Measure of the total number of dissolved particles per litre of solution
73
If HCl and estrogen were each placed in water, which solution would have a higher osmolarity?
HCl, because it would dissolve into H+ and Cl- ions. Estrogen does not dissolve.
74
Tonicity
Effect of osmolarity on cell shape; affects cell volume, which then affects shape
75
3 levels (?) of tonicity and effect on a cell
Isotonic: equal concentrations of nonpenetrating solutes on either side of a membrane, cell is unaffected
Hypertonic: higher concentration of nonpenetrating solutes outside a membrane, net decrease in solvent entering cell
Hypotonic: higher concentration of nonpenetrating solutes inside a membrane, net increase in solvent entering cell
76
Primary vs. Secondary Active Transport
Primary: uses energy from hydrolysis of ATP to change the shape of a pump
Secondary: uses energy from an ion's electrochemical gradient to transport other solutes via a pump
77
Symport vs Antiport
Symport: secondary active transport where both solutes move in the same direction
Antiport: secondary active transport where both solutes move in different directions
78
Vesicular Transport
Lipids form vesicles, which engulf solutes to move them across the plasma membrane.
79
Exocytosis
Vesicles move substances out of the cell
80
Endocytosis
Vesicles bring substances into the cell.
81
Receptor-Mediated Endocytosis
Ligand binds to a receptor on the plasma membrane, and a vesicle forms to bring the ligand into the cell
82
Phagocytosis
Cells engulf large solids (e.g. worn-out cells, bacteria, viruses); protects body from disease
83
Pinocytosis
Cells intake small droplets of ECF; no receptors involved!
84
Peroxisomes
- Similar structure to lysosomes
- Contain enzymes that use molecular oxygen to oxidize organic compounds and produce H2O2
- Abundant in liver cells
