Biology 212 2nd exam
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- Glial cell:Neuron Ratio
- 50:10
- Glial Functions (6)
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Creates Myelin Sheath
Creates a matrix that connects neurons
Helps guide development of neural pathways
Blood-brain-barrier (tight junctions)
Provides metabolic support for neurons
NEW: appear to communicate chemically with other - What is "membrane potential"
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Charge difference between the inside and outside of the membrane
An "Electrical signal" of the nervous system is a change in the membrane potential
- What determines the value of the membrane potential at any time?
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Chemical gradients
Electrical gradients
Selective permeability of the membrane
- Why is the resting membrane potential negative?
- At rest, the membrane is 25X more permeable to K+ than Na+, resulting in the interior of the cell to become more negative because positive charges are leaving the cell.
- What is Action potential?
- A rapid, transient change in the membrane potential from negative to positive and back again.
- What allows the charges in membrane potential to occur during an AP? (2)
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Changes in MEMBRANE PERMEABILITY due to opening and closing of VOLTAGE-GATED channels
Resultant movement of ions along their chemical and electrical gradients
- What cell makes up the Myelin Sheath?
- Schwann cell
- What is Saltatory conduction?
- Ions jumping from node of ranvier to node of ranvier
- What do neurotransmitters prevent?
- the intake of sodium into the cell.
- What is a sensation?
- Electircal impulses that reach the brain via sensory neurons
- what is a perception?
- Interpretation of electrical impulses by the brain
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Mechanoreceptors stimulated by...
- Physical deformation (touch)
- Nociceptors stimulated by...
- Inflamed/Damaged tissue
- Thermoreceptors stimulated by....
- heat/cold
- Chemoreceptors stimulated by....
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specific molecule types
(ex. osmoreceptors-detect chenges in solutes, Gustatory (taste) Olfactory (smell))
- Electromagnetic receptors stimulated by...
- Electromagnetic energy (Light energy)
- Light detection eyes detect...
- Light intensity/directionally
- Compound Eyes detect....
- Movement, consists of multiple ommatidia
- Single-lens eye detects.....
- movement, one enlarged ommatidia.
- Functions of the Cornea (2)
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Transparent
allows light into eye
- Funtion of pupil
- Regulates amount of light entering eye
- Function of lens
- Focuses image onto back of eye
- Funtion of Rhodopsin
- (light absorbing pigment) triggers signal-transduction pathway
- What are components of a Hydrostatic Skeleton (3)
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Fluid-filled compartments provide support
Movement by circular and longitudinal muscles
Ideal for aquatic life (can't support body vertically)
- Components of an Exoskeleton (3)
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Rigid encasement deposited on surface of organism
(Made of Chitin/Calcium carbonate)
Muscles attach from outer "shell" to interior body
must be periodically shed
- Components of endoskeleton (2)
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Rigid internal skeleton supporting body
Can grow with organism; relatively lightweight
- Functions of Muscle (5)
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Movement
Maintain posture
Support soft tissue
Guard entrance/exit
Maintain body temperature
- Connective tissue layers of Muscle (3)
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Epimysium
Perimysium
Endomysium
- Name the Triad of Muscle Fibers (3)
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Transverse Tubules
Sacroplasmic reticulum
Myofibrils
- Name the two myofilaments (2)
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Actin
Myocin
- Sarcomere are...
- repeating units of myofilaments
- List the events in muscle contrations (6)
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1. Acetylcholine released from synaptic knob
2. ACh binds to receptor on motor end plate; generates AP
3. Action potential conducted along Sarcolemma
4. AP descends into muscle fiber via T-tubles
5. AP trigger - List the events in Cross Bridging events (6)
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1. Ca++ binds with proponin; exposes active sites on actin
2. Myosin head (cocked) binds with active site
3. Myosin head pivots-pulls actin forward
4. ATP binds to myosin head; head detaches and re-cocks
5. Myosin head binds to active -
Skeletal Muscle
1. Filament Organization
2. Control Mechanism
3. Calcium Source
4. Contraction
5. Energy Source
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1. Sarcomeres along myofibrils
2. Neural
3. Sarcoplasmic reticulum
4. Rapid onset: tetanus can occur:rapid fatigue
5. Aerobic/Anaerobic
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Cardiac Muscle
1. Filament Organization
2. Control Mechanism
3. Calcium Source
4. Contraction
5. Energy Source
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1. Sarcomeres along myofibrils
2. Automaticity (pacemaker cells)
3. SR/across sarcolemma
4. Slower onset: no tetanus; fatigue-resistant
5. Aerobic
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Smooth Muscle
1. Filament Organization
2. Control Mechanism
3. Calcium Source
4. Contraction
5. Energy Source
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1. Scattered in sarcoplasm
2. Automaticity, neural, hormonal
3. Across sarcolemma
4. Slow onset: tetanus can occur, fatigue-resistant
5. Aerobic
- What is a motor unit?
- A single motor neuron and all the muscle fibers innervated by it (all-or-none)
- What is recruitment and its purpose?
- addition of motor units to produce smooth, steady muscle tension
- what is a Twitch?
- Single stimulus-contration-relaxation sequence
- What is homeostasis?
- the process of maintaining a relatively stable internal environment
- What are the three different classes of hormones (3)
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1. Amino Acid Derivatives (ex Epinephrine)
2. Peptide Hormones (ex Insulin)
3. Lipid Derivatives (ex. Testosterone)