Muscle and Nerve Tissue Flashcards
what does it consist of
What are muscle tissues
Muscle tissues consist of elongated cells that use energy from the hydrolysis of ATP to generate force.
As a result of contraction, muscle tissue produces body movements, maintains posture, and generates heat.
What are the three muscle tissue types
- Skeletal
- Cardiac
- Smooth
Skeletal muscles location
Usually attached to bones via tendons
Skeletal muscles strucutre
Long cells; striated; multi-nucleated
Skeletal muscles function
Motion, posture, heat, protection. Contraction under conscious control (mostly voluntary)
What is the shape of skeletal muscles
Cylindrical
What are the smallest and longest skeletal muscle
Starpedius and sartorious
What is the function of starpedius muscle
Stabilises the smallest human bone (stapes in the ear); prevents hypercaucis; tympanic reflex; Bell’s Palsy; facial n
What is the function of the sartorious muslce
‘Checking for gum’, Hip: flexor, abductor, lateral rotator
Knee: flexor
Starpedius function in ear
- Modify the intensity of sound get transmitted to hearing
- Tightens the confirmation of bone in ear
- Keep sound within comfortable range
what are myofibrils
More or less fill the cytoplasm (sarcoplasm) of the muscle fibre and extend its entire length within the cell
The striations of skeletal muscle fibres are due to what
Highly organised arrangement of myofibrils within the cells
What is this
Skeletal muscle tissue
The myofibrils are composed of what two types of filaments
Thin filaments: mostly actin
Thick filaments: myosin
What are myofibrils
More or less fill the cytoplasm (sarcoplasm) of the muscle fibre and extend its entire length within the cell
What are myofilaments
They do not extend the length of the muscle fibre but are arranged in compartments called sarcomeres.
What is a sarcomere
The basic functional unit of a myofibril/ Z disc separates sarcomeres.
What are the different connective tissues of the skeletal muscle?
Epimysium, perimysium, endomysium, sarcolemma, sarcoplasm
What is epimysium of the skeletal muscle
Surrounds the anatomical structure
What is the perimysium of the skeletal muscle
Around fasicles
What is the endomysium of the skeletal muscle location
Is around muscle fibres (“cell”) - layer for capillaries/nerves).
What is the sarcolemma of the skeletal muscle
The actual cell of the plasma membrane
What is the sarcoplasm
The cell cytoplasm
What do the thick and thin myofilaments overlap to produce
The striations in the myofibril
A band of the myofilament
Dark; middle part; contains all the thick filaments
I band of the myofilament
Think filaments; but no thick filaments
H zone of the myofilaments
Thick filaments but no thin filaments
M line of the myofilament
Middle of sarcomere (holds thick filaments together)
Z disc of the myofilament
Passes through centre of I band (between sarcomeres) made up of ‘actinins’ - that link filaments of adjacent sarcomeres
What is titin of the myofilament
Links Z to M line; provides resting tension in I band, molecular spring.
Is this relaxed, partially contracted, or maximally contracted muscle
Relaxed muscle
Is this relaxed, partially contracted, or maximally contracted muscle
Partially contracted
Is this relaxed, partially contracted, or maximally contracted muscle
Maximally contracted muscle
Cardiac muscle (location structure and function)
Located in the heart. Still have actin and myosin
Structure: striated; branched; single central nucleus; fibres join end to end through intercalated discs.
What do intercalated discs in cardiac muscle contain
- Desmosomes (bind intermediate filaments) - provide adhesion in contraction
- Gap Junctions (communication) - coordinated rapid conduction
Is cardiac muscle voluntary or involuntary
Involuntary
In this intercalated disc, what is the red and blue arrow pointing to
Red: Gap junction
Blue: desmosome
What is this
Cardiac muscle tissue
Smooth muscle location
In the walls of hollow internal structures
What are examples of where smooth muscle are located and used for
- Intestines (peristalsis)
- blood vessel walls (constriction)
Also
* iris of eye
* reproductive
* digestive
* respiratory
* urinary
* skin erector pili
Is smooth muscle voluntary or involuntary?
Involuntary
Smooth muscle structure
Short, small, spindle-shaped,.
Non-striated, and has a single central nucleus.
How are smooth muscle fibres striated
Smooth muscle fibres are non-striated, but still have bundles of thin (actin) and thick (myosin) filaments.
* Thin filaments (actin) attatch to “dense bodies”, functionally similar to Z discs
What is this
Smooth muscle tissue
What connects to dense bodies in smooth muscle cells
Thin filaments (actin) and also intermediate filaments (non-contractile elements)
What is the major protein in dense bodies
Actinin
What happens during contraction in smooth muscle cells
Tension is transmitted to the intermediate filaments (don’t contract) and the cell twists as it contracts.
And their functions within NS
What are the two main subdivisions of the nervous system
Central nervous system (brain and spinal chord)
Peripheral nervous system (all nervous systems outside CNS)
Two divisions of the PNS
Sensory/afferent division: information to the CNS
Motor/efferent division: Information from CNS to the organs (muscles and glands).
What does nervous system help to
Maintain homeostasis (along with the endocrine system)
Initiates voluntary movement
Responsible for perception, behaviour and memory.
Activities grouped by the nervous system are grouped under three major functions
i. Sensory
ii. Integrative
iii. Motor
What is sensory function of the nervous system
Detection of internal and external stimuli and transfer to CNS
What is the intergrative function of the nervous system
Analysis and storing of information
What is the motor function of the nervous system
Stimulation of effectors (e.g muscles and glands) through PNS i.e motor here means “effector”.
The nervous tissue consists what two types of cells
Neurons (nerve cells that can be very large)
Neuroglia (supportive cells - usually small)
What are the longest cells in the body and what control do they have
Neurons - conscious and unconscious control
What is this
Neuron of spinal cord
What are neurons
Have a cell body into which short, branched dendrites convey nerve impulses (action potentials) and from which a longer, single axon conducts nerve impulses to another neuron or tissue.
Neurons - dendrites
The receiving/input part of the neuron
Neurons - axons
Carries the nerve impulse away from the neuron. It is the output portion of the neuron.
True or false: neurons do not divide, have high metabolic rates and die without CO2
True
What are multipolar neurons and where are they most common,y found
Have two or more dendrites and a single axon.
Most common neurons in CNS and all motor neurons (control skeletal muscle) are in the class.
What is this
Multi-polar neurons
What are the two distinct process of bipolar neurons
- 1 dendritic process (can branch at tip but not at cell body)
- 1 axon
Structure of bipolar neurons
- Has cell body between axon and dendrite
Function of bipolar neurons
Have special sesne organs (sight, smell, hearing) that relay information from receptor to neurons.
What is this
Bi-polar neurons
What are unipolar neurons
- The dendrites and axons are continuous
- Cell body off to one side
- Very long
Where type of neurons are most sensory nerves found in
Unipolar neurons
What is this
Unipolar neurons
What are anaxonic neurons
Are rare and function poorly understood
Anatomy cannot distinguish dendrites and axons.
Whereare anaxonic neurons found
Brain and special sense organs
systems
Where are neuroglia found
In both CNS and PNS
more or less
Which is bigger: neuroglia or neurons
Neuroglia is smaller than neurons, but more numerous
Neuroglia do not propagate __ _____ but can _________.
Action potentials, communicate
Function of neuroglia
- Physical structure of nervous tissue
- Repair framework of nervous tissue
- Undertake phagocytosis
- Nutrient supply to neurons
- regular interstitial fluid in neural tissue
What are the 4 different classifications of CNS Neuroglia
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
What is the most numerous neuroglia and what is its structure
Astrocytes - star shaped, largest neuroglia in size
What neuroglia is this
Astrocytes
CNS Neuroglia - Astrocytes function
- Star-shaped, largest most numerous of neuroglia
- Support and repair
- Communicate with neurons
- maintain environment around neuron
- maintain the blood-brain barrier via endothelium. Wraps around vessels ad influence their permeability.
CNS Neuroglia - Oligodendrocytes
Form insulating multi-layered myelin sheath (protein-lipid layer) around CNS axons
Can myelinate more than one neuron cell’s axon. Accelerate the action potential.
CNS Neuroglia - Microglia
Phagocytic (resident macrophages) for protection
What does this image show
Inactive microglia
What does this image show
Active microglia
what it produces and
CNS Neuroglia - what do ependymal cells produce
Produces cerebrospinal fluid (CSF)
what it lines
CNS Neuroglia - where ependymal cells found
Lines the CSF-filled ventricles in the brain and the central canal of the spinal cord
Where are the ependymal cells located?
Ventricles and in other locations where CNS is found
Do ependymal cells have cilia and microvilli
Yes
What is the function of CSF
Mechanical buffers; move nutrients and waste
What cells are shown
Ependymal cells
What are the two types of PNS neuroglia?
Schwann and satellite cells
PNS - Schwann cells
PNS version of oligpdendrocyte
Form insulating myelin sheath around axons or can just support and surround several non-myelinated azons
What are neurilemmas
The outer surface of the Schwann cells
What can a single Schwann cell form, and what is this function
The internode of many unmyelinated axons. This stabilises the position of these axons and isolates them from chemicals in surrounding interstitial fluid.
PNS - Satellite cells
Surround neuron cell bodies
Support and fluid exchange
Smooth muscle - thin and intermediate filaments
Thin filaments attach to ‘dense bodies’. and functionally similar to Z disc. Intermediate filaments (non-contractile elements) also connect to dense bodies.
Where are anaxonic neurons found
brain and special sense organs
