Muscular Flashcards
Muscles constitute what percentage of body mass?
40-50%
Anatomical into of muscles
Myofibrils
Functional unit of muscles
Sarcomere
Are muscle cells excitable?
Some, yes. Eg: heart cells (AV nodes, SN nodes, Purkinje)
Define HYPERPLASIA
Increase in cell number
Define HYPERTROPHY
Increase in cell size
Define ATROPHY
Malnourished
Give substance to the following terms with respect to muscular tissue:
Hyperplasia
Hypertrophy
Atrophy
Hyperplasia is not seen in muscles
Hypertrophy is seen in muscles (gym- body building)
Atrophy (PEM eg Kwashiorkar, Marasmus)
Why are certain muscles striated?
All muscles contain contractile actin and myosin proteins . In some muscles these proteins are arranged in an orderly manner (eg skeletal, cardiac) while in others (eg smooth) they ARE PRESENT, just not arranged in an orderly manner.
Do smooth muscles have troponin?
No, they have CALMODULIN
Cardiac muscles are multinucleate. Comment.
FALSE. Uninucleate.
Skeletal muscles are branched/Unbranched.
UNBRANCHED Skeletal muscles.
Which tissue out of the three classifications, is FUNCTIONALLY SYNCITIAL
Cardiac
Smooth muscles show fast/slow contractions.
Sloooooow
Smooth muscles are thickly wrapped with sarcolemma
FALSE
With respect to the outer connective sheath (epi-, Peri-, endo-) which ones are present in Cardiac
Endomysium
Out of the three connective sheaths which wrap muscles, which is absent in smooth muscles
Epimysium.
Smooth muscles have ENDOMYSIUM AND PERIMYSIUM
Skeletal muscles have which three connective sheaths which cover it
EPIMYSIUM, PERIMYSIUM, ENDOMYSIUM
Define fascia, fascicle
One tube (fibre?) + ENDOMYSIUM = Unit A
Many units of A group together + PERIMYSIUM= Fascicle
Many fascicles come together and get covered by EPIMYSIUM to form fascia
Why do red muscle cells have SLOW contractions (why white ones have fast muscle contractions)
Because red muscles cells may be having higher count of mitochrmondria which supplements their higher rate of contractions, but they have LESS SARCOPLASMIC RETICULUM, hence a bit short on the calcium reserves which is seen in their slower contractions.
Can muscle development be altered by training?
Yes, however HYPERPLASIA is never seen in muscle cells, HYPERTROPHY is. And accordingly, specific, customized training can shape the body in the a particular way.
Eg. Marathon runners and sprinters have different prominent skeletal muscle types. Former will have more developed red muscle fibres while the sprinters will have more white muscle fibres.
Classification of smooth muscles based on gap junction.
Single unit (bladder) and multi unit muscles (iris, erector pili, large blood vessels)
Where all do we find gap junctions (name three examples)
Epithelial
Cardiac
Single unit smooth muscles
Brain tumour term
Glioma
Which neuron is in direct contact with the external environment
Olfactory neuron
Which neurons can divide
Olfactory neurons (in direct contact with the environment hence have to be replaced) and astrocytes (repair and form other cells)
Term perikaryon refers to
Cyton/Soma i.e. cell body of a neuron
Node to node conduction is aka
Saltatory conduction
One Schwann cell wraps around one/many axons?
ONE axon (monogamous)
Schwann cells are absent in non medullated neurons
False. They just don’t secrete the myelin sheath
Neurilemma is continuous/discontinuous?
CONTINUOUS.
Neurilemma is absent in?
C N S
Since Schwann cells are absent in CNS
Oligodendrocytes are present in?
CNS
Name two neuroglial cells which are responsible for myelin sheath formation
Oligodendrocytes (CNS, no neurilemma, wraps around many axons) Schwann cells (PNS, neurilemma, wraps around only one axon)
Neurons of which nervous system are completely non reparable
Central nervous system
How do oligodendrocytes wrap around the axons of neurons?
They have cytoplasmic processes.
Grey matter? White matter? Say whaaaaaat?
Myelin sheath gives white colour.
Brain: outer grey and inner white
(Periphery has the soma and dendrites, GREY while the inner portion has the axon which has the Myelin sheath which is white in colour)
Similarly, spinal cord: outer white, inner grey
Unipolar neurons are present in
Embryonal neurons
Sponges have what kind of neurons
Trick question haha
Parkinson’s and Alzheimer’s are incurable “degenerative” diseases, why?
CNS relates and neurons of CNS are strictly irreparable.
Knee jerk reflex stimuli travels where
Dorsal root ganglion (pseudounipolar neuron)
Myelinated and non myelinated? Classification of?
Axons
Which neuroglial cells form blood brain barrier
Astrocytes
Which neuroglial cells repair and form other cells?
Astrocyte
