Intro to Muscle
1. produce movement
2. maintain posture and body position
3. stabilize joints
4. generate heat
What are the three functions of the nervous system?
Sensory input
Integration
Motor output
What are the four regions of the brain?
1. Cerebral hemispheres
2. Diencephalon
3. Brain Stem
4. Cerebellum
What are the steps to cross bridge cycling?
1. Cross bridge formation. Myosin head attaches to actin myofilament forming a cross bridge.
2. Power stroke. ADP + pi are released and the myosin head pivots and bends, changing to its low energy state. Actin is pulled toward the m line.
3. Cross bridge detachment. After ATP attaches to myosin, the link between myosin and actin weakens and the myosin head detaches
4. Cocking of myosin head. As myosin hydrolyzes ATP to ADP + Pi, the myosin head returns to its prestroke high – energy or cocked position.
What is ohms law
The relationship between voltage, current, and resistance. Current = Voltage/ Resistance
What are the two regulatory proteins of actin and what are their functions?
Tropomyosin - spirals around the actin core to stiffen and stabilize, but also blocks myosin binding site
Troponin - globular protein with three polypeptide subunits. One anchors troponin to actin, one binds tropomyosin and positions it, and the other binds calcium
What are the two parts of the nervous system? Any subdivisions of the second part?
Central nervous system
Peripheral nervous system
Sensory
Motor
What is the function of sulci
Divide the hemispheres into lobes.
What are the different types of muscle contractions
Isometric – No change in length as work is performed.
Isotonic – When force exceeds load
- Concentric
- Eccentric
What are the two types of signals that change the membrane potential?
Graded potential – Incoming signals operated over short distances.
Action potential – Long distance signals of axons.
What are the two channels that allow a change in membrane potential of the muscle cell and what are their functions?
Chemically gated ion channels - opened by chemical messengers
Voltage-gated ion channels - open or close in response to changes in membrane potential
What are the neuroglia that make up the central nervous system?
1. Astrocytes
2. Microglial
3. Ependymal cells
4. Oligodendrocytes.
What are the motor areas of the brain (3)?
Primary motor cortex, premotor cortex, broca’s area
What are the factors that impact cross bridge attachments
1. Frequency of stimulation
2. Amount of muscle fibers recruited
3. Relative size of fibers
4. Degree of stretch.
What are the two types of movement on an axon?
Anterograde movement – away from cell body
Retrograde – Toward cell body.
What are the four big picture steps in muscle contraction?
1. Events at the neuromuscular junction
2. Muscle fiber excitation
3. Excitation contraction coupling
4. Cross bridge cycling
What are the three structural classifications of Neurons?
Multipolar neurons
Bipolar neurons
Unipolar neurons
What are the sensory areas of the brain(10)
Primary somatosensory cortex, somatosensory association cortex, primary visual cortex, visual association area, primary auditory cortex, auditory association area, vestibular cortex, olfactory cortex, gustatory cortex, and visceral sensory area.
What are the factors that influence velocity and duration of contraction?
Fiber type, load, and recruitment
How is the myelin sheath formed in the PNS vs the CNS.
PNS – Formed by schwann cells
CNS – Formed by oligodendrocytes.
What are the steps to the events at the neuromuscular junction
1. AP arrives at the axon terminal
2. Voltage gated ca+ channels open and calcium moves down the concentration gradient into the axon terminal.
3. Calcium entry causes acetylcholine to be released by exocytosis.
4. ACH diffuses across cleft and binds ACH receptors on the sarcolemma of the motor end plate.
5. ACH binding opens chemically gated ion channels. Na+ moves into the muscle fiber and K+ moves out.
6. ACH effects are terminated by acetylcholinesterase.
What are the functional classifications of neurons?
1. Sensory/afferent
2. Motor/efferent
3. Interneurons
Function of the thalamus vs hypothalamus
Thalamus – acts as a relay station for information coming into the cerebral cortex.
Hypothalamus - Controls the ANS, initiates physical response to emotions, regulates body temp, regulates food intake, regulates water balance and thirst, regulates sleep-wake cycles, and controls endocrine system functions.
What are two functional characteristics of muscle fiber type?
1) Speed of contraction
2) Major pathways for forming ATP
- Oxidative
- Glycolytic
What is the difference between saltatory and continuous conduction?
Continuous – AP propagation along nonmyelinated axons.
Saltatory Conduction – AP generation in myelinated axon. Current is maintained an moves rapidly to next sheath gap.