Exam 3 Flashcards
What are the three types of Muscle?
- Skeletal
- Cardiac
- Smooth
What are the characteristics of all muscle tissue
- Excitability:ability to change membrane potential
- Contractibility: ability to shorten
- Extensibility: Ability to stretch
- Elasticity: ability to recoil to original length
What are the functions of muscle tissue?
Produce movement
Maintain posture
stabilize joints
generate heat
Longest muscle cells, attached to the skeleton, striated, voluntary
Skeletal muscle
Only in the heart, striated, involuntary
Cardiac
In the walls of hollow visceral organs, no striations, involuntary
Smooth
All Muscle tissue has what?
Muscle fibers
Blood vessels
Nerve Fibers
Connective tissue
Covering that surround the whole muscle (dense irregular connective tissue)
Epimysium
A group of muscle fibers.
Fascicle
What is skeletal muscle made of
Multiple fascicles
Covering around fascicle (dense irregular connective tissue)
Perimysium
Connective tissue that surrounds each muscle fiber
Endomysium
Long, cylindrical, and multinucliate
Muscle fibers (muscle cells)
What is the plasma membrane of muscle fibers called
Sarcolemma
What are the characteristics of sarcoplasm that makes it different compared to the cytoplasm
- Has a large amount of glycogen in glycosomes
- has Myoglobin which is unique to muscle fibers but similar to hemoglobin (Stores Oxygen in muscle cells)
- Contains myofibrils alongside the usual organelles
What are contractile elements of muscle cells
Myofibrils
What makes up 80% of muscle cell volume?
Myofibrils
Why is skeletal muscle striated?
Because of Actin + Myosin
Made from repeating series of dark A bands and light I bands
Striations
Lighter stripe in middle of A band (relaxed muscle)
H Zone
Skeletal muscle are also referred to as
Muscle Fibers
Which of the following is most associated with the attachments formed between muscles and bones
- Epimysium
- Endomysium
- Perimysium
Epimysium
Which of the following is the smallest strucutral unit
- Myofibril
- sarcomere
- Myofilament
- Fascicle
- Muscle fiber
Myofilament
_____ is chiefly composed of the protein myosin that forms thick filaments
A band
Which of the following does not change length during shortening resulting from a muscle contraction
Thin myofilaments
Bisects H zone and A band
M line
Bisect I band
Z disc
Where thick filaments are found
A band
Where thick filaments are NOT found
I band
Region between Z discs, is a functional contractile unit and are what form a myofibril
Sarcomere
Fibers within a sarcomere
Myofilaments
Run the width of the A band
Thick filaments
What cells are excitable
Nerve cells and muscle cells
Where are the T tubules in the muscle
The space between the sarcoplasmic reticulum cisterna
Protein that forms Z discs, anchors filaments, and connects adjacent myofibrils
Alpha actin
Hold adjacent thick filaments together
Desmin
Fine protein strands that form M line
Myomesin
Composed of giant protein, titin and runs from Z discs to myosin.
Elastic filaments
What hold thick filaments in place and are extensible whe n muscle stretching
Elastic filaments
the protein that makes up thick filaments
Myosin
what troponin binds actin
TnI
What troponin binds to tropmyosin and positions it on actin
TnT
What Troponin binds calcium ions
TnC
What determines that position of tropomyosin
The shape of troponin
What determined the ability of the muscle contracting?
The position of the tropomyosin
What is the endoplasmic reticulum of muscle cells
Sarcoplasmic Reticulum
What surrounds each myofibril and is a network for tubules
Sarcoplasmic reticulum
The junctions between the A band and I band in the SR that gets thicker
Terminal Cisternae
In a ________ muscle, the thick and thin filaments overlap at the ends of the A band and not in the H Zone
Relaxed
In a _________ muscle the thick and thin filaments overlap more such that the H zone gets smaller of fully disappears
Contracted
The active site on actin is exposed and Ca2+ binds troponin
Step 1 of Cross bridge
The myosin head forms a cross bridge with actin
Step 2 of Cross bridge
Powerstoke begins, and during that the myosin head bends and ADP and phospate are released
Step 3 of Cross bridge
A new ATP molecule attaches to the myosin head causing the cross bridge to detach
Step 4 of Cross bridge
ATP hydrolyzes to ADP and phosphate, which returns myosin to original state
Last Phase of Cross bridge
Which of the following events occurs during the relaxation phase of muscle twitch?
- Binding of Ca2+ to thin filaments
- Release of Ach into the synaptic cleft
- Active transport of Ca2+ into the SR
- Depolarization of T tubules
Active transport of Ca2+ ot the SR
Increased Contractile force due to recruitment results from ________.
Simulation of a muscle by increasing numbers of activated somatic motor neurons.
What is expected to occur during the recovery period following strenuous exercise?
Glycogen is formed from glucose
What explains the decreased contractile force generated by a stretched muscle?
Stretching of myofibrils within the muscle fibers decreases the overlap between thin and thick myofilaments
What is a similarity between smooth muscle and skeletal muscle?
Both smooth muscle and skeletal muscle are contain thin and thick myofilaments
What are the functions of the central and peripheral nervous system?
Gather sensory information both internal and external
- Process info, filter and interpret info
- Produce a response: voluntary or involuntary
What are the parts central nervous system?
The brain and the spinal cord
What are the parts of the Peripheral nervous system?
nerves not located in the CNS
- Spinal and cranial nerves
What is the name of the process that sends impulse to the CNS
Afferent
What are the two types of afferent fibers and what are the locations they send impulses to
Somatic: Skin muscle and joints
Visceral: organs in the ventral body cavity
What is the name of the process that nerves carry away impluses from the CNS exit
Efferent
What are the two types of efferent nerves
-Somatic (voluntary)
- autonomic (involuntary)
What are the two types of autonomic nerves?
Sympathetic (fight of flight)
Parasympathetic (rest and digest)
What part of the body are somatic sensory fibers and is it afferent or efferent?
the skin (afferent)
What part of the body are visceral sensory fibers and is it afferent of efferent
The stomach (afferent)
What part of the body is motor fiber of somatic nervous system and is it afferent of efferent?
Skeletal muscle (efferent, voluntary motor nerve)
What part of the body are sympathetic motor fibers of ANS and is it efferent or afferent, somatic or visceral
The heart (efferent, involuntary, visceral)
What part of the body is a parasympathetic motor fiber os ANS and is is afferent or effrent, somatic or viceral
The bladder
(involuntary, efferent, visceral nerve)
What is the nervous tissue in PNS and CNS made of
- nerve cells (neurons)
- Supporting cells (neuroglia)
Information messengers, Most diverse kind of cells in the body
Nerve cells (neurons)
Smaller than neurons and out number them 9:1
Neuroglia
What are the Neuroglia of the CNS
- Astrocytes
- Microglia
- Ependymal cells
- Oligodendrocytes
What is the most abundant of glial cells
Astrocytes
What are the three basic jobs of astrocytes
- helpform a network on which neurons grow
- anchor neurons to capillaries
- mop up leaked neurotransmitters
have a protective role and are apart of our immue system by turning into macrophages and phagocytose for debris
Microglia
Line cavities of the brain and spinal cord and are ciliated to keep cerebrospinal fluid moving
Ependymal cells
What are the two neuroglia of PNS?
- Satellite cells
- Schwann cells (neurolemmocytes)
Which part of the nervous system transmitts impulses that most directly lead to and increase in heart rate.
Autonomic Nervous system
Glia cells that have processes that form myelin sheaths around the CNS nerve fibers
Oligodenrocytes
What cells form Myelin sheaths
Schwann Cells
What are the receptive regions on a neuron?
Dendrites
What is the cell body on a neuron
Soma
What is the conducting region on a neuron
Axon
What is the out put region on a neuron
Nerve terminal
What maintains the shape and integrity of a soma
Neurofibrils
What are clusters of cells bodies in the CNS called
Nuclei
What are clusters if cell bodies in the PNS called
Ganglia
What transmits incoming information to axon hillock and are branching extensions of the cell body?
Dendrites
How many axons are there per neuron?
One
What is the projection of the cell body and arises from the axon hillock
Axon
Have numerous dendrites and have 3 oe more cells processes
Multipolar nuerons
Have 2 processes and are rare but found in the retina of the eye, sense organs, and olfactory mucosa
Bipolar nuerons
have 1 process that emerges from the cell body and most are sensory neurons in PNS
Unipolar Neurons
What two neuroglia form insulating coverings called myelin sheaths?
Oligodenrocytes and Schwann Cells
Which type of neuroglia form epithelia layers within the central nervous system
Ependymal cells
What is the purpose of the central nervous system
filter, interpret, or ignore electrical information
What are the smallest neurons in the body
Interneurons
Anterograde
From the cell body to terminal (kinesin)
retrograde
From the terminal to cell body (dynenin )
What direction does electrical current go?
From the cell body to the nerve terminal
How do neurons communicate with each other?
by generating electrical signals which are just the movement of charged ions.
What are the two types of electrical signals
Graded Potential and action potential
In the dendrites and cel body the electrical signal called a
Graded potential
In the axon the electrical signal or nerve impulse is called an
Action potential
The dendrites in the body have ______ and or mechanically gated channels
Chemically
Th axons, sarcolemma and T-tubules have _____ gated channels
Voltage
Where do graded potentials occur
In the dendrites (receptive region) and cell body
- are due to the opening of chemically gated ion channels.WH
Where do action potentials occur
On the axon (sacrolemma and (T-tubules)
- Are based on the large degreel of voltage
The membrane potential moves toward 0 mV, the inside becoming less negative (more positive)
Depolarization
The membrane potential increases, the inside becoming more negative
Hyperpolarization
which event directly explains that polarity of the resting membrane potential of an unstimulated neuron plasma membrane
Leakage of K+ out of the neuron
(K+ diffusing out of the cell through the leakage channels causes the cell to become more negative inside
What is the resting membrane potential?
-70 mV
What is threshold
-55 mV this is needed to result in a full action potential
A motor neuron along with the muscle fibers supplies is
Motor unit
Each skeletal muscle fiber is controlled by a neuron at a single
Neuromuscular junction
In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and
myosin
What is the cause of rigor mortis?
Calcium influx into the sarcoplasm after death
The refractory period in which the muscle will NOT contract if stimulated occurs during __________ of the muscle cell.
repolarization
What produces a voltage difference across the membrane
Resting membrane potential = The inside of the membrane being more negative compared to the outside.
Polarized state
The inside of the cell is more negative than the outside
How do you get electrical current to flow?
BY depolarizing the membrane
The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the
Action potential
When does a graded potential occur
- a chemical (neurotransmitter) binds to the chemically gated ion channels on dendrites in the cell body
- the ion channels open allowing sodium ions to flow into the cell
- the inflow of postitive charge causes a depolarization of the membrane
4 . the more sodium that flows in, the greater the depolarization - the movement of the positively charges sodium in the cell is electrical current
- the sodium flows a certian distance before the sodium potassium pump picks it up and sends it back out of the cell, thus the current becomes weakers and weaker the further it travels from the site of initial stimulus
If electrical current (Na+) travels towards the axon hillock and changes the membrane potential from -70 to -55 then a large ____________ will occur
Depolarization
What is the fastest group in nerve fibers
Group A
- speed of conduction is up to 150 m/s or 300 mph
Mostly somatic sensory + motor fibers serving
- the skin
-skeletal muscles
- joints
fastest group
Group A
Autonomic Nervous system + motor fibers
- small somatic sensroy fibers (pain +small touch fibers)
- medium diameter
- speed of conduction is up to 15 m/s or 40 mph
Group B
Same fibers as group b
- small diameter
unmyelinated
slow speed of conduction
Group C
Immune systems makes antibodies to myelin –> destruction of myelin sheath
multiple sclerosis
motor nueron diease
degeneration of motor nerves - sporadic 90-95% of cases
ALS (amyotrophic lateral scelosis
What does a Neuromuscular junction 9at the end of the axon branches) consist of
Motor neerve terminal, the synaptic cleft, and the motor end plate
Contains synaptic vesicles (sacs contaiing neurotransmitter)
Nerve terminal
A chemical message
Neurotransmitter
At the NMJ the NT is
Acetylcholine (ach)
SOD 1
Protects us from free radicals
individuals with ALS have small amounts SOD1
Motor nerves are
efferent, voluntary, somatic
The gap between nerve terminal and sarcolemma
Synaptic cleft
When is acetocholine released?
When calcium enters the nerve terminal and binds to chemically gated ion channel
What are the three places in your neuromuscular nervous system where there are voltaged gated ion channels
Axon, sarcolemma, and T tubules
A dimple in the sarcolemma which are junctional folds in tf the sarcolemma
Motor end plate
What is at the motor end plate
chemically gated ion channels
What is the location of chemically gated ion channels
dendrites
What type of paraylisis is it when the muscles contract and will not relax
( in patients that have ahd a stroke0
Spastic paralysis
What type of paralysis is it when the muscles will not contract
Flaccid paralysis
no electrical signal = no muscle contraction
A botanical neuromuscular blocking agent that binds to ach R and keeps it from binding to cause flaccid paralysis ( competitive antagonist)
Tubocurarine
drugs that block Ach r
anticholineasterase
One of the most potent poisons known and is found in Japanese puffer fish
- block sodium ion channels and is deaht by flaccid paralysis of respiratory muscles
Tetrodotoxin
Autoimmune disease caused when the immune system developed antibodies to Ach receptors, destruction by macrophages
Myasthenia Gravis
From bacteria clostridium botulinum that blocks Ach relese from the nerve terminal and creates botulism. -paraylisis of muscles
Botulinus Toxin (BOTOX)
temporary removal of pain while fully conscious that black voltage gated Na+ channels
Local anesthetics (lidocaine, xylocaine, procaine, cocaine
