Term
| What are 7 muscular system functions? |
|
Definition
1) Body Movement
2) Maintenance of posture, joint stability
3) Respiration
4) Protection of body heat
5) Communication
6) Constriction of organs and vessels
7) Heart beat |
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Term
| What are 4 properties of muscle? |
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Definition
1) Contractility - ability of a muscle to shorten with force
2) Excitability - Capacity of muscle to respond to a stimulus
3) Extensibility - Muscle can be stretched to its normal resting length and beyond to a limited degree.
4) Elasticity - Ability of muscle to recoil to original resting length after stretch |
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Term
| What are 3 main structures of muscle? |
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Definition
1) Sarcolemma (sarcoplasm) - "muscle hask" or cell membrane
2) Muscle fiber - smooth and skeletal muscle elongated
3) Myofilaments - actin and myosin microfilaments (more actin than myosin) |
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Term
| What are 3 types of muscle? and list characteristics of each |
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Definition
1) Skeletal - multinucleated, voluntary movement, attached to bone or connective tissue
2) Smooth Muscle - non striated, 2 layers, forces fluid through tubes, found in hollow organs like the stomach and intestines
3) Cardiac Muscle - found in heart, striated, single nucleus, pumps the blood |
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Term
| Intracellular support of the muscle occurs through what? |
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Definition
| The sliding filament Model |
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Term
| What role do Actin myofilaments and Myosin have to do with the sliding filament model? |
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Definition
| Actin myofilaments slide over myosin to shorten sarcomeres. Actin and myson do not change length. Shortening sarcomeres are responsible for skeletal muscle contraction. |
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Term
| During relaxation, what happens to the sarcomeres? |
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Definition
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Term
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Definition
| When the myosin heads latch on to myosin binding sites on actin in the thin filaments, and the sliding begins. |
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Term
| What is an action potential? |
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Definition
| an electrical current along the sarcolemma |
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Term
| List in order, the process, from resting potential, to depolarization and repolarization. |
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Definition
1. Electrical conditions of a resting (polarized) sarcolemma. The outside is positive with Na+ while the inside is negative with K+
2. Depolarization and generation of the action potential - Na+ diffuses into the cell making the inside more positive (depolorizing the cell). If the stimulus is strong enough, then an action potential is initiated
3. Propagation of the action potential - The positive charge inside the cell continues to spreads throughout the cell until an action potential occurs
4. Repolarization - Na+ begins to leave the cell while K+ re enters the cell. The cell is repolarized (restored) and is negative on the inside again. |
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Term
| What diffuses across the synaptic cleft and attaches to receptors on the sarcolemma, opening ion channels and initiating depolarization of the sarcolemma? |
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Definition
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Term
| What divides the axon terminal and the muscle fiber? |
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Definition
| The synpatic cleft which is filled with a gel-like extracellular substance. |
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Term
| During repolarization, a muscle fiber is said to be in a __________ period, because the cell cannont be stimulated again until repolarization is complete |
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Definition
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Term
| List the 6 steps in excitation-contraction coupling (Na+ and Ca2+): |
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Definition
1. Net entry of Na+ initiates an aciton potential which is propagated along the sarcolemma and down the T tubules
2. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca2+ release from terminal cisternae of SR into cytosol
3. Calcium ions bind to troponin
4. Contraction!
5. Removal of Ca2+ by active transport into the SR after the action potential ends.
6. Tropomyosin blockaged restored, blocking myosin biding sites on actin. |
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Term
| The mechanism where an action potential causes muscle fiber contraction involves what 6 things? |
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Definition
1. Sarcolemma
2. Transverse or T tubules
3. Terminal Cisternae
4. Sarcoplasmic reticulum
5. Ca2+
6. Troponin |
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Term
| List the four steps in muscle fiber contraction? (once the biding sites on actin are exposed) |
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Definition
1. Myosin head attaches to the actin myofilament, forming a cross bridge
2. Inorganic phosphate generated in the previous contraction cycle is released, initiating the power (working stroke). The myosin head pivots and bends as it pulls on the actin filamnet sliding it toward the M line. Then ADP is released
3. As new ATP attaches to the myosin head, the link between myosin and actin weakens, and the cross bridge detaches.
4. As ATP is split into ADP and inorganic phosphate, the myosin head is energized. |
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Term
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Definition
| A single motor neuron and all the muscle fibers innervated. |
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Term
| Strength of contractions range from weak to strong depending on what? |
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Definition
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Term
|
Definition
| A muscle contraction in response to a stimulus that causes action potential in one or more muscle fibers. |
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Term
| What are the three phases of a muscle twitch? |
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Definition
1. Latent period
2. Period of contraction
3. Period of relaxation |
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Term
| Which phase takes the longest and why? |
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Definition
| Period of relaxation takes longer, due to Ca2+ uptake, restoration of ATP, myofilament has to stretch out again. |
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Term
| What are slow twitch fibers and give me an example of one? |
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Definition
Muscle fibers that take longer to react
- The soleus (slowleus) |
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Term
| What are fast twitch muscle fibers and give me an example of one? |
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Definition
Fibers that are faster to react, but fatigue much faster as well.
-Gastrocnemius (calf), Extraocular muscle |
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Term
| Which type of muscle fiber fatigues quicker? |
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Definition
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Term
| What is unfused or incomplete tetanus? |
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Definition
| Muscle fibers partially relax between contractions |
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Term
| What is fused or complete tetanus? |
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Definition
| No relaxation between contractions |
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Term
| What is multiple motor unit summation? |
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Definition
A whole muscle contracts with a small or large force depending on number of motor units stimulated to contract.
Calling more and more muscle fibers into play. It controls the force of contraction. |
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Term
| What are the four steps in multiple motor unit summation? |
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Definition
1. Twitch
2. Wave summation
3. Unfused (incomplete) tetanus
4. Fused (complete) tetanus |
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Term
| As frequency of action potentials increase, frequency of contraction increases or decreases? |
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Definition
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Term
| What is multiple-wave summation? |
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Definition
| Muscle tension increases as contraction frequencies increase |
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Term
| The size of the contraction depends on what? |
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Definition
| The size of the stimulus or intensity |
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Term
| Increased muscle force is due to what 3 things? |
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Definition
1. Recruiting more motor units - motor unit summation
2. Increasing stimulus intensity - Stimulus summation
3. Increasing stimulus frequency |
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Term
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Definition
| A graded response that occurs in muscle rested for prolonged period of time. Each subsequent contraction is stronger than previous until all equal after few stimuli. (the stair step in muscle tension while stimuli is at a constant strength) |
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Term
| What are the two types of muscle contraction? |
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Definition
1. Isometric - no change in length but tension increases. Postural muscles of the body
2. Isotonic - change in length but tension is constant. |
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Term
| List the two types of Isotonic contractions: |
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Definition
1. Concentric - muscle shortens (going against gravity)(flexing up)
2. Eccentric - muscle lengthens (makes you sore) |
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Term
| What provides immediate energy for muscle contraction? |
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Definition
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Term
| What 3 sources can we produce ATP through? |
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Definition
1. ATP-PC system - creatine phosphate - during resting conditions stores energy to synthesize ATP. 10-15 seconds of energy. 1 ATP per CP, creatine
2. Anaerobic respiration - Occurs in absence of oxygen and results in breakdown of glucose to yield ATP and lactic acid. Glycolysis. 30-40 seconds. 2 ATP per glucose
3. Aerobic respiration - Requires oxygen and breaks down glucose to produce ATP, CO2, water, and heat. More efficient than anaerobic means. Lasts for hours. produces 38 ATP |
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Term
| What 4 factors affect the force of a muscle contraction? |
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Definition
1. The number of muscle fibers stimulated - more fibers = more force
2. Relative size of figers - bulkier muscle = more force
3. Frequency of stimulation - can lead to tetanus
4. Degree of muscle strength - length tension relationship |
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Term
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Definition
| A smooth, sustained muscle contraction resulting from high - frequency stimulation |
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Term
| With regards to force and myosin heads, what happens when you stretch the muscle. What happens if the muscle is more compact? |
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Definition
| If you stretch the muscle you have less force. The more compact the muscle is the more myosin head sites are available so you have more force. Having too short of muscle also decreases force. This also does not allow for many mysoin head sites. The muscle has to be a perfect length in order to utilize your strength. |
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Term
| What four factors which influence contractile force? |
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Definition
1. The number of muscle fibers stimulated
2. The relative size of the fibers
3. Frequency of stimulation
4. The degree of muscle stretch |
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Term
| Heavier loads take (longer/shorter) time for muscle to shorten and the muscle shortens (more/less). |
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Definition
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Term
| What is fatigue? List 3 types of fatigue: |
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Definition
Fatigue is a decreased capacity to work and reduced efficiency of performance.
1. Psychological - Depends on emotional state of individual
2. Muscular - Results from ATP depletion
3. Synaptic - Occurs in the neuro-muscular junction due to lack of acetylcholine. |
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Term
| What are slow twitch fibers? What type are they? |
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Definition
| Slow twitch fibers are high-oxidative fibers. They are Type I. very slow (high myoglobin content) |
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Term
| What are fast twitch fibers? What type are they? |
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Definition
Fast twitch fibers are low oxidative. They consist of Type IIa and Type IIx
Type IIx - true fast twitch muscle fiber. Fast glycolytic fibers.
Type IIa - intermediate muscle fiber (more in between fast and slow). Fast oxidative/glycolytic fibers |
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Term
| What is the slowest, middle, and fastest muscle fibers? |
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Definition
Type I - slowest
Type IIa - middle (in between slow and fast)
Type IIx - fastest |
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Term
| What 3 roles does skeletal muscles play? |
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Definition
1. Agonist - biceps (elbow flexion)
2. Antagonist - triceps (elbow flexion)
3. Synergist - working together |
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Term
| What are some effects of aging on skeletal muscle? |
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Definition
1. Reduced muscle mass
2. Increased time for muscle to contract in response to nervous stimuli
3. Reduced stamina
4. Increased recovery time
5. Loss of muscle fibers
6. Decreased density of capillaries in muscle. |
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Term
| Rate of muscle mass loss increases after what age? |
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Definition
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Term
| What can you do to improve strength and endurance? Can age-related loss in muscle mass be completely eliminated? |
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Definition
Regular exercise training
No, cannot completely eliminate the age-related loss in muscle mass. |
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Term
| List characteristics of smooth muscle: (Striations? How many layers? Contracts in response to what?) |
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Definition
1. Non-striated
2. 2 layers - longitudinal, circular
3. Contracts in response to sudden stretch
4. Have a single nucleus
5. Relatively constant tension
6. E-C coupling differs from skeletal. |
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Term
| What function does smooth muscle serve? |
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Definition
| Regulates the size of organs, forces fluid through tubes, controls the amount of light entering the eye, and produces "goose flesh" in the skin |
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Term
| Where is smooth muscle located? |
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Definition
| Smooth muscle is in hollow organs such as the stomach and intestine. |
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Term
| What is attached to smooth muscle cells which relax and contract the muscle? |
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Definition
| Intermediate filament bundles attached to dense bodies. |
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Term
| Give some characteristics of cardiac muscle structure? |
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Definition
| Cardiac muscle cells are cylindrical and striated and have a single, centrally located nucleus. They are branched and connected to one another by intercalated discs, which contain gap junctions. |
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Term
| Functions of cardiac muscle? Where is it found? |
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Definition
Pumps the blood; under involuntary control.
Located in the heart....dumbass |
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Term
| What substance regulates contraction of cardiac muscle? |
|
Definition
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Term
| Give characteristics of skeletal muscle. (structure, function, location) |
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Definition
Structure - appear striated. cells are large, long, and cylindrical, multinucleated
Function - movement of the body; under voluntary control.
Location - attaches to bone or other connective tissue. |
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Term
| What 3 things help skeletal muscle? |
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Definition
1. Connective tissue
2. Blood vessels
3. Nerve fibers |
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Term
| What 5 structures in skeletal muscle consist of connective tissue? |
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Definition
1. External lamina
2. Endomysium - Surrounds individual muscle fibers
3. Perimysium - Surround each fascicle -(endomysium-wrapped muscle fibers)
4. Fasciculus
5. Epimysium - An overcoat surround the whole muscle. |
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Term
| A muscle fiber consists of how many cells? |
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Definition
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Term
| What are the 4 components of the nervous system? |
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Definition
1. Brain
2. Spinal Cord
3. Nerves
4. Sensory receptors |
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Term
| What 4 things is the nervous system responsible for? |
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Definition
1. Sensory perceptions
2. Mental activities
3. Stimulating muscle movements
4. Secretions of many glands |
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Term
| What are the two subdivisions of the nervous system? What does each subdivision consist of? |
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Definition
1. Central nervous system (CNS) - Consists of the brain and spinal cord
2. Peripheral nervous system (PNS) - Consists of the cranial and spinal nerves and communicates lines between the CNS and the rest of the body. Two divisions - a)Sensory division - Afferent receptors transmit to CNS and b) Motor division - efferent fibers transmit from CNS to effectors (muscles and glands) |
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Term
| What does afferent mean? What does efferent mean? |
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Definition
Afferent means traveling towards
Efferent means traveling away from. |
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Term
| What are the two divisions of the Motor or efferent subcategory? |
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Definition
1. Somatic nervous system - Somatic motor (voluntary) - conducts impulses from the CNS to skeletal muscle
2. Autonomic nervous system - Visceral motor (involuntary) - conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands.
a) Sympathetic which mobilizes body systems during activity.
b) Parasympathetic which conserves energy and promotes housekeeping functions during rest. |
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Term
| What is a neuron? Give 5 characteristics of a neuron: |
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Definition
A neuron is the primary functional unit of the nervous system which receive and send out stimuli.
1. Extreme longevity
2. Amitotic
3. High metabolic rate
4. Highly irritable
5. Action potential |
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Term
| List the 4 components of a neuron: |
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Definition
1. Cell body or soma
2. Dendrites - Input
3. Axons - Output
4. Terminals (up to 1000s) |
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Term
| What are neuroglia or glial cells in the PNS and what do they do? |
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Definition
There are two types of neuroglia cells in the PNS
1. Satellite cells - surround neruon cell bodies located in the PNS.
2. Schwann cells - form myelin sheaths around the larger nerve fibers in the PNS.
They support and protect neurons. |
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Term
| Which neuroglia cells are found in the CNS? |
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Definition
1. Astrocytes - most abundant, they cling to neurons and their synaptic endings, and cover nearby capillaries, supporting and bracing the neurons and anchoring them to the nutrient supply lines, the blood capillaries.
2. Microglia - monitor the health of neurons that it touches
3. Ependymal cells - creates a fairly permeable barrier between the cerebrospinal bathing the cells of the CNS. |
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Term
| What is going on with Multiple Sclerosis? |
|
Definition
Hot spots on an MRI represent plaque where nerve bundles are de-myelinating. It is the autoimmune degradation of motor nerve myelination. The immune system attacks and destroys the myelin sheath around the axons. When myelin is lost, action potentials can no longer be conducted.
Symptoms: numbness, parastesisas, dizziness, vision problems, depression, vertigo, urinary problems, paralysis, fatigue, memory problems
-No definitive diagnostic test.
-No cures
-Outcomes - loss of function, independence. |
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Term
| What are the three structural classifications of neurons? |
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Definition
1. Multipolar - Several dendrites and one axon Ex. muscles
2. Bipolar - One dendrite and one axon (2 parts) Ex. The eye
3. Unipolar - A neuron with a single axon. Ex. The skin (ouch hot!) |
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Term
| The most abundant structural classification neuron is what? |
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Definition
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Term
| Schwann cells surround the ____ while Satellite cells surround the ___ ____ |
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Definition
| Schwann cells surround the axon while Satellite cells surround the cell body |
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Term
| The node of ranvier is found where? |
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Definition
| in between schwann cells along the length of the axon. |
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Term
| What are the 5 total neuroglia cells? |
|
Definition
1. Astrocytes - structural support
2. Ependymal cells - line ventricles of brain and circulate cerebrospinal fluid.
3. Microglia - protect CNS from infection
4. Oligodendrocytes - Form myelin sheaths around axons within CNS
5. Schwann cells - form myelin sheatsh around axons. Within PNS. |
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Term
| What are the four phases of action potentials? |
|
Definition
1. Rest - Na+ and K+ channels closed and inside of the cell is more negative than the outside
2. Depolarization - Na+ channels open allowing Na+ to come in
3. Repolarization - Na+ channels close and K+ channels open. Restoration of the cell bringing back the negative charge inside the cell
4. Hyperpolarization - K+ channels remain open and the cell becomes more negative than it is at resting potential |
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Term
| What kind of channels open and close in response to changes in the membrane potential? |
|
Definition
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|
Term
| How do chemically gated channels work? |
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Definition
| They open when the appropriate chemical (in this case a neurotransmitter) binds. |
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|
Term
| What are three factors that affect action potential propagation? |
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Definition
1. Diameter of axon
2. Myelination
3. Temperature |
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|
Term
| What is it called when conductions skip along the nodes of ranvier? |
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Definition
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|
Term
What is the refractory period?
Absolute?
Relative? |
|
Definition
The refractory period is the time when you are not going to receive another cation potential
Absolute - will not give a substantial action potential
Relative (hyperpolarization) - can give a substantial action potential as long as there is enough stimulus to cover the hyperpolarization. |
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|
Term
What is convergence?
Divergence? |
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Definition
Convergence is where there are two inputs to a single downstream neuron
Divergence is where the axon splits and you have two downstream neurons. |
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Term
What is spatial summation?
Temporal summation? |
|
Definition
Spatial summation - adding together based on space (summing from several different presynaptic neuron)
Temporal - adding based on time (summing several EPSP's from one presynaptic neuron) |
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|
Term
What is an EPSP?
What is an IPSP? |
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Definition
An EPSP is an excitatory postsynaptic potential - causes more of a depolarization, action potential and cell response. Excitatory neurons!
An IPSP is an inhibitory postsynaptic potential - causes more of a hyperpolarization, basically it inhibits an action potential by making the cell more negative on the inside thus not allowing depolarization to occur |
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Term
| What are the five steps of the depolarization events at a chemical synapse? |
|
Definition
1. Voltage Gate Ca2+ channels open
2. Ca2+ signals exocytosis of neurotrans
3. Neurotrans bind post synpatic membrane receptor
4. Ion channels open - depolarization
5. Neurotransmitter degraded enzymatically (or taken up by pre-synaptic terminal or astrocyte, or diffuses away from the synapse) |
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Term
| Acetylcholine is a very important neurotransmitter. Tell me it's functional classes and the sites where it is secreted: |
|
Definition
Functional class: Excitatory, direct action
Sites where secreted: In the CNS - widespread throughout cerebral cortex, hippocampus, and brain stem
In the PNS - All neuromuscular junctions with skeletal muscle |
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Term
| List the 4 other neurotransmitters: |
|
Definition
1. Norepinephrine - Excitatory or inhibitory - "feeling good"
2. Dopamine - Excitatory or inhibitory - "feeling good"
3. Serotonin - mainly inhibitory
4. Histamine |
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|
Term
Mechanoreceptors =
Thermoreceptors =
Photoreceptors =
Chemoreceptors =
Nocioceptors = |
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Definition
Mechanoreceptors = sense of movement, pressure, or tension
Thermoreceptors = sense of temperature
Photoreceptors = sense of sight (light)
Chemoreceptors = any sensory receptor selective for chemicals
Nocioceptors = sensing pain |
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Term
| What are the 5 steps of a reflex arc? |
|
Definition
1. Receptor
2. Sensory neuron
3. Integration center (interneuron)
4. Motor neuron
5. Effector |
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|
Term
What is reciprocal inhibition?
What is crossed extensor reflex? |
|
Definition
Reciprocal inhibition is when one muscle contracts and another relaxes. EPSP vs. IPSP.
Crossed extensor reflex is when you pull a muscle away from a hot stove for example, and another muscle goes the other way to balance the body out. |
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|
Term
IPSP relaxes/contracts?
EPSP relaxes/contracts? |
|
Definition
IPSP relaxes
EPSP contracts |
|
|
Term
| What is the major role of the sarcoplasmic reticulum? |
|
Definition
| to regulate intracellular levels of ionic calcium: It stores calcium and releases it on demand when the muscle fiber is stiulated to contract |
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|
Term
| What do T - tubules do for muscle? |
|
Definition
| Because T tubules are continuations of the sarcolemma, they can and do conduct impulses to the deepest regions of the muscle cell and to every sarcomere. |
|
|
Term
| Which bands make up striations? |
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Definition
| Dark A bands and light I bands. |
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|
Term
| The sarcolemma is the plasma membrane of many muscle fibers and each muscle fiber is made up of what? |
|
Definition
| many rodlike myofibrils that run parallel to its length. |
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Term
H zone?
M line?
Z disc?
Sarcomere? |
|
Definition
H zone - cut in half by an m line
M line - Middle line
Z disc - on outside (2 lines)
Sarcomere is the region of a myofibril between two successive Z discs. |
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|
Term
The thick filaments in muscle consist of what?
The thin filaments in muscle consist of what? |
|
Definition
Thick filaments are composed primarily of the protein myosin
Thin filaments are composed chiefly of the protein actin. |
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|
Term
| List in order, the functional subdivisions and their associated conective tissue wrapping, from smallest to largest. |
|
Definition
1. Myofilament
2. Sarcomere - composed of myofilaments
3. Myofibril - composed of sarcomeres arranged end to end
4. Muscle fiber - surrounded by the endomysium
5. Fassicle - Surrounded by a perimysium
6. Muscle - covered externally by the epimysium. |
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