Muscle Tissue and Anatomy Quiz

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Questions and Answers

What type of connective tissue sheath completely surrounds an entire skeletal muscle?

Perimysium

Endomysium

Epimysium (correct)

Myofascia

Which type of muscle tissue is characterized by the presence of striations and is involuntary?

Cardiac muscle (correct)

Smooth muscle

Epithelial muscle

Skeletal muscle

What is the primary function of myofibrils in a muscle cell?

Energy production

Contraction (correct)

Signal transmission

Storage of nutrients

Which of the following best describes the sarcoplasm in a skeletal muscle fiber?

It contains a high concentration of myoglobin and glycogen. Signup and view all the answers

Which connective tissue sheath surrounds a group of muscle fibers known as a fascicle?

Perimysium Signup and view all the answers

What is the primary role of the sarcoplasmic reticulum in muscle fibers?

To store and release calcium ions Signup and view all the answers

Which structure bisects the H zone vertically in a sarcomere?

M line Signup and view all the answers

What composes the thick filaments in muscle fibers?

Myosin with heavy and light chains Signup and view all the answers

The I band in a sarcomere is primarily composed of which type of filament?

Thin filaments Signup and view all the answers

Which protein structure forms the boundary between adjacent sarcomeres?

Z disc Signup and view all the answers

What is the significance of T tubules in muscle contraction?

They allow for the electrical impulse to reach deep into the muscle cell Signup and view all the answers

What arrangement characterizes the filaments in a sarcomere?

One thick filament surrounded by six thin filaments Signup and view all the answers

What structure is formed by the interaction of terminal cisterns and T tubules?

Triad Signup and view all the answers

During muscle contraction, which part of the thick filament interacts with the thin filament?

The myosin globular head Signup and view all the answers

What type of proteins are tropomyosin and troponin?

Regulatory proteins Signup and view all the answers

Which type of neuron is primarily involved in transmitting impulses from sensory receptors towards the CNS?

Unipolar Signup and view all the answers

What is the primary type of neuron found in the dorsal root ganglia?

Unipolar Signup and view all the answers

How many axons can a single oligodendrocyte wrap at once in the CNS?

60 Signup and view all the answers

What do you call the multipolar neurons that lie between motor and sensory neurons?

Interneurons Signup and view all the answers

What type of processes does a bipolar neuron have?

One axon and one dendrite Signup and view all the answers

In the structure of a myelin sheath in the CNS, which feature distinguishes it from other types?

Formed by oligodendrocytes Signup and view all the answers

Which of the following is NOT a region of the brain?

Cerebellum Signup and view all the answers

Which type of neuron is primarily responsible for carrying impulses from the CNS to effectors?

Motor Signup and view all the answers

What happens to thin and thick filaments during muscle contraction?

They slide past each other, increasing overlap. Signup and view all the answers

Which process allows myosin heads to bind to actin?

Release of calcium ions. Signup and view all the answers

When cross bridges form, what physical changes occur to the sarcomere?

H zone disappears. Signup and view all the answers

Which division of the nervous system is responsible for voluntary muscle control?

Somatic Nervous System. Signup and view all the answers

What distinguishes the sympathetic division from the parasympathetic division?

Sympathetic division prepares the body for fight or flight. Signup and view all the answers

What is the role of sensory (afferent) nerve fibers in the nervous system?

Transmit impulses from effectors to CNS. Signup and view all the answers

Which statement about neuroglia is true?

They support and protect neurons. Signup and view all the answers

What does the autonomic nervous system specifically control?

Involuntary actions such as heartbeat. Signup and view all the answers

Which of the following best describes the function of motor (efferent) nerve fibers?

They transmit signals from the CNS to effector organs. Signup and view all the answers

What type of potential represents the stored energy from food in the context of muscle efficiency?

Chemical potential. Signup and view all the answers

What is the primary function of astrocytes in the central nervous system?

To provide structural support to neurons. Signup and view all the answers

Which type of cell in the central nervous system is responsible for producing cerebrospinal fluid?

Ependymal cells Signup and view all the answers

What is the function of microglial cells in the central nervous system?

To act as the primary immune defense. Signup and view all the answers

What distinguishes oligodendrocytes from Schwann cells?

Oligodendrocytes form myelin sheaths around multiple axons. Signup and view all the answers

What is the role of the satellite cells in the peripheral nervous system?

To surround and support neuron cell bodies. Signup and view all the answers

Which statement correctly describes the difference between ganglia and nuclei?

Ganglia are clusters of neuron cell bodies in the PNS. Signup and view all the answers

What is the composition of the myelin sheath?

A myelin, a whitish protein lipid substance. Signup and view all the answers

What is the primary function of nodes of Ranvier in myelinated fibers?

To increase the speed of nerve impulse transmission. Signup and view all the answers

How do non-myelinated fibers compare to myelinated fibers regarding signal transmission speed?

Non-myelinated fibers transmit signals more slowly. Signup and view all the answers

What feature characterizes white matter in the nervous system?

Contains dense collections of myelinated fibers. Signup and view all the answers

What is the primary function of the thalamus within the diencephalon?

Acts as a relay station for information coming into the cortex Signup and view all the answers

What structure separates the two cerebral hemispheres?

Longitudinal fissure Signup and view all the answers

Which layer of the meninges is the strongest and adheres to the skull's inner surface?

Dura mater Signup and view all the answers

What is the primary role of the hypothalamus?

Regulate homeostasis and control the autonomic nervous system Signup and view all the answers

Which component is responsible for producing cerebrospinal fluid?

Choroid plexus Signup and view all the answers

What is the name of the structure that connects the two cerebral hemispheres?

Corpus callosum Signup and view all the answers

Which part of the brain is primarily responsible for coordinating balance and muscle movement?

Cerebellum Signup and view all the answers

What is the primary role of Purkinje cells in the cerebellum?

Synapse with deep cerebellar nuclei Signup and view all the answers

What is the function of the cardiovascular center in the medulla oblongata?

Adjusts heart rate and blood vessel diameter Signup and view all the answers

What two types of matter primarily compose the cerebral cortex?

Gray and white matter Signup and view all the answers

Which of the following lobes is NOT a main division of the cerebral hemispheres?

Hippoocampal Signup and view all the answers

Which of the following structures is part of the brainstem?

Pons Signup and view all the answers

What is the primary role of cerebrospinal fluid (CSF)?

Cushion and protect the brain Signup and view all the answers

What distinguishes the central sulcus in the brain?

It separates the pre-central gyrus of the frontal lobe from the post-central gyrus of the parietal lobe Signup and view all the answers

Study Notes

Muscle Tissue Types

Skeletal muscle—attaches to bones, controls movement, and has obvious striations
Cardiac muscle—forms the heart walls, has striations, and cannot be consciously controlled
Smooth muscle—lines internal organs, lacks striations, and is involuntary

Connective Tissue Sheaths

Epimysium: dense irregular connective tissue surrounding the entire muscle
Perimysium: fibrous connective tissue surrounding fascicles (bundles of muscle fibers)
Endomysium: fine areolar connective tissue surrounding each muscle fiber

Microscopic Anatomy of Skeletal Muscle Fiber

Sarcolemma: plasma membrane of a muscle fiber
Sarcoplasm: cytoplasm of a muscle fiber, containing glycogen for energy storage and myoglobin for oxygen storage
Myofibrils: densely packed, rod-like elements within a muscle fiber, responsible for 80% of the cell's volume
Sarcomeres: repeating functional units of myofibrils, giving a striated appearance
Myofilaments: actin (thin) and myosin (thick) filaments within sarcomeres
Striations: alternating dark (A bands) and light (I bands) regions within sarcomeres
A band: contains thick filaments and overlapping thin filaments
I band: contains only thin filaments
H zone: lighter region within the A band, where filaments don't overlap
M line: supporting protein in the center of the H zone
Z discs: boundaries of adjacent sarcomeres, anchored to thin filaments

Thick and Thin Filaments

Actin myofilaments (thin): extend across the I band and part of the A band, anchored to Z discs
Myosin myofilaments (thick): extend along the length of the A band, connected at the M line
Thick filaments are composed of myosin proteins with a tail and globular head.
Thin filaments are made primarily of actin, along with tropomyosin and troponin regulatory proteins.

Sarcoplasmic Reticulum and T-Tubules

Sarcoplasmic reticulum: network of smooth endoplasmic reticulum tubules surrounding each myofibril, storing and releasing calcium ions
T tubules: tube-like extensions of the sarcolemma that penetrate into the muscle fiber, increasing surface area
Triad: area formed from a T-tubule and 2 terminal cisternae of the sarcoplasmic reticulum

Sliding Filament Model of Contraction

During contraction, thin filaments slide past thick filaments, causing the actin and myosin filaments to overlap more
A nerve impulse triggers the release of calcium ions, releasing troponin
Cross-bridges are formed when myosin heads bind to actin filaments
Using ATP, myosin heads pull on actin, causing the thin filaments to slide inward
The Z discs are pulled closer together, and the sarcomere shortens.

Neuromuscular Junction

The point of contact between a motor neuron and a muscle fiber
Acetylcholine (ACh) is released, initiating a muscle contraction

Mechanical, Chemical and Voltage Potentials

Mechanical potential: The strength of your muscles to move things.
Chemical potential: The fuel stored in cells from food (energy).
Voltage potential: The electric charge inside your cells, like a battery waiting to fire.
Action potential: The electrical signal that causes things to happen, like muscle movement or nerve signals.

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Description

Test your knowledge on the different types of muscle tissue, their connective tissue sheaths, and the microscopic anatomy of skeletal muscle fibers. This quiz will cover key concepts such as skeletal, cardiac, and smooth muscle, as well as the structure and function of muscle fibers and their components.