90 Questions
What is the primary function of Purkinje fibres in the heart?
Facilitating rapid electrical communication
Which type of protein complexes are present in intercalated discs?
Desmosomes
Where are Purkinje fibres mainly located within the heart?
Ventricles (lower chambers)
Which ions flow through gap junctions in the intercalated discs for coordinated contractions?
Calcium and sodium
What is the specialized function of desmosomes within the intercalated discs?
Providing adhesion between cells
In terms of control, is cardiac muscle voluntary or involuntary?
Involuntary
What is the central region in a sarcomere where thin filaments slide inward and overlap?
H Zone
Which component of a sarcomere remains relatively constant in length during contraction?
A Band
What happens to the I Band and H Zone when a muscle is maximally contracted?
They disappear
What is the central position within a sarcomere that contains thick myosin filaments?
A Band
Where are thin filaments in a sarcomere attached that leads to Z discs coming closer together during muscle contraction?
M line
What leads to the shortening of an entire muscle due to the shortening of individual sarcomeres?
Sliding of thin filaments within sarcomeres
What distinguishes smooth muscle from skeletal muscle?
Non-striated appearance
How are thin filaments in smooth muscle cells anchored?
To dense bodies
What is the function of intermediate filaments in smooth muscle cells?
Structural support
Which system is considered the command center of the nervous system?
Central Nervous System (CNS)
What is the main function of the brain in the CNS?
Memory and coordination
How does smooth muscle contraction differ from skeletal muscle contraction?
Twisting motion
What is the role of dendrites in a neuron?
Acting as receptionists and listening for incoming messages
Which type of neurons are the 'social butterflies' of the nervous system?
Multipolar Neurons
Where are multipolar neurons commonly found?
Central Nervous System (CNS)
What happens to neurons without oxygen?
They deteriorate quickly
What distinguishes bipolar neurons from multipolar neurons?
Having two distinct processes
Which type of neurons are responsible for controlling skeletal muscles?
Motor Neurons
What is a characteristic of an anaxonic neuron?
Their exact function is still a bit of a mystery.
Where are anaxonic neurons typically found?
In the brain and special sense organs.
What is a key function of neuroglia in the nervous system?
Acting as the structural framework for nervous tissue.
How do neuroglia differ from neurons in terms of communication?
Neuroglia don't play the action potential game like neurons.
What role do neuroglia play in the nervous system when neurons need fixing?
Step in as the repair crew for neurons.
Which part of the nervous system has a higher volume occupied by neuroglia compared to neurons?
Central Nervous System (CNS)
Why are muscle fibres in skeletal muscles considered multinucleate?
To push the nuclei to the side due to the elongated shape
What is the primary function of skeletal muscles in terms of body movements?
Producing force for movement
Why are only skeletal muscles considered voluntary?
They are under conscious control
What role do tendons play in skeletal muscles?
Anchoring the muscle fibres to the bones
How do muscle fibres generate force for body movements?
Through the hydrolysis of ATP
What is the significance of striations in skeletal muscle fibres?
'Reflecting the organized arrangement of myofibrils
What happens to the I Band and H Zone when a muscle is maximally contracted?
They narrow and eventually disappear as thin filaments slide inward
What is the primary function of Z discs in a sarcomere?
To attach thin filaments and allow sliding during contraction
Which region of the sarcomere contains the dark A band?
M Line
What is the role of myosin heads during muscle contraction?
They progressively pull thin filaments toward the M Line
What function do Z discs serve in sarcomeres?
Provide attachment points for thin filaments allowing sliding
What happens to the A band during muscle contraction?
It remains relatively constant in length
What is the function of desmosomes within intercalated discs?
Provide adhesion between adjacent cells
Where are Purkinje fibres predominantly located within the heart?
Ventricles
Which component within the intercalated discs allows ions to flow for coordinated contractions?
Gap Junctions
How are Purkinje fibres best described in terms of function?
Conduct electrical signals
What is the primary job of Purkinje fibres within the heart?
Conduct electrical signals
Which type of muscle tissue contains single central nuclei, striations, and intercalated discs?
Cardiac muscle
What is the primary function of dendrites in a neuron?
Sensing and receiving incoming messages from other neurons
Which key feature distinguishes multipolar neurons from other neuron types?
Having multiple dendrites branching out from the cell body
In terms of function, how do axons in neurons differ from dendrites?
Axons carry messages away from the cell body
What characterizes bipolar neurons among the neuron types?
Having two distinct dendritic processes
Where are multipolar neurons commonly found in the body?
Central Nervous System (CNS)
What analogy best describes the function of axons in neurons?
Neurons' delivery guys
What is the main function of microglia?
Gobbling up debris and foreign invaders
How do ependymal cells contribute to the nervous system?
Producing cerebrospinal fluid
What is a key feature of ependymal cells?
Having cilia and microvilli for flow and sampling
Where are Schwann cells mainly located?
Wrapping around PNS axons with myelin sheath
What is the primary function of cerebrospinal fluid (CSF)?
Acting like a cushion
What distinguishes ependymal cells from Schwann cells?
Presence of cilia and microvilli
What is the primary role of microglia in the nervous system?
Protecting the brain by phagocytosis
What distinguishes ependymal cells from microglia and Schwann cells?
Cuboidal shape and presence of cilia/microvilli
What is the main function of Schwann cells in the peripheral nervous system?
Insulating axons with myelin sheath
Where would you typically find ependymal cells within the nervous system?
Lining ventricles and central canal
Which cell type acts as the 'personal bodyguards' for axons in the peripheral nervous system?
Schwann Cells
What is a key function of cerebrospinal fluid (CSF) in the nervous system?
Acting as a cushion for brain and spinal cord protection
What distinguishes smooth muscle from skeletal muscle based on the text?
Presence of striations
How does smooth muscle contraction differ from skeletal muscle contraction?
Direction of tension transfer
Where are Z discs located in relation to thin filaments in a sarcomere during muscle contraction?
Coming closer together
What is the primary function of dendrites in a neuron according to the text?
Sensory reception
Which type of nervous tissue is described as the quiet achiever in the body by the text?
Smooth muscle fibers
What is the distinguishing feature of central nervous system (CNS) according to the text?
Function as the command center
What is the main function of the integrative function of the nervous system?
Storing memories and experiences
Which division of the peripheral nervous system is responsible for bringing information to the CNS?
Sensory/Afferent Division
What is the primary role of sensory nerves in the nervous system?
Bringing information to the CNS
Which part of the nervous system can be likened to a messenger carrying information between the brain and the body?
Peripheral Nervous System
What distinguishes the sensory function of the nervous system from the integrative function?
Detecting internal and external stimuli
In terms of the PNS, what is the role of motor nerves?
Taking instructions from CNS to organs
What is a unique characteristic of astrocytes among CNS neuroglia?
Chatting with neurons through gliotransmitters
How do oligodendrocytes differ in myelination compared to Schwann cells?
Oligodendrocytes myelinate multiple axons, while Schwann cells myelinate one axon
Which function is specific to microglia among CNS neuroglia?
Serving as the bodyguards of the nervous system
What role do astrocytes play in maintaining the brain's environment?
Regulating ions like sodium and potassium
What distinguishes astrocytes from oligodendrocytes in terms of their structure?
Being star-shaped and forming a syncytium network
Which feature of oligodendrocytes provides a speed boost to action potentials along axons?
Creating myelin sheaths around CNS axons
What is the main role of the Z disc in a sarcomere?
Links filaments of adjacent sarcomeres
How is the H Zone visualized in the muscle structure?
Imagine it as the empty space in the middle of a chocolate bar
What is the primary function of Titin within a sarcomere?
Acts like a molecular spring
In muscle contraction, what does the M Line primarily do?
Hold the thick filaments together
What best describes the composition of the Z Disc?
Consists of actinins
How does the sliding filament mechanism help understand muscle contraction?
By showing how actin and myosin slide past each other to shorten sarcomeres
Test your knowledge on the structure of a sarcomere and the sliding interaction between actin and myosin filaments. Learn how myosin heads attach to actin filaments and pull them towards the center of the sarcomere during muscle contraction.
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