Cells and tissues: muscle and nervous Flashcards
Muscle tissue function
elongated cells or fibres (myocytes) that use energy from hydrolysis of ATP to generate force. results in contractions, posture, heat
types of muscle tisse
skeletal
cardiac
smooth
skeletal muscle tissue
fibrous and cylindrical attached to bones via tendons and appear striated. voluntary and conscious control. long cells. nuclei pushed to side
smallest muscle
stapedius, tympanic reflex, controls tension on ear bones to prevent deafening
bells palsy
hyperacususis from stapedius being paralysed
longest muscle
sartorius: leg, hip to tibia, check for gum leg muscle, flexor
striations
due to myofibrils in cytoplasm (sarcoplasm) that run the length of cell.
myfibril
myofilaments arranged in compartments called sarcomeres (defined by Z discs).
made of
thin filaments: actin
thick filiments: mysosin
epimysium
surrounds anatomical muscle
perimysium
around fascicles (lots of myocytes together)
endomysium
around muscle fibres, capillaries/nerves here
sarcolemma
muscle cell plasma membrane
sarcoplasm
muscle cell cytoplasm
Bands of myfibril
A band: middle, with all thick filaments
I Band: only thin, no thick
H zone: thick but no thin. dynamic and contracts
M line: middle of sarcomere that holds thick together
Z disc: passes through I band and made if actinins that like filaments of adjacent sarcomeres
cardiac muscle
striated and branched with a single central nucleus. joined by intercalated disc. found in heart and involuntary non-conscious control
intercalated disc
made of desmosomes that bind intermediate filaments and gap junctions
smooth muscle
walls of hollow internal structures. change shape and contract. spindle shaped and involuntary control. non striated and contractile mechanism can change. single central nucleus
dense bodies
provide structural connections for contractile elements, made of actinin. connected to intermediate filaments.
intermediate filaments in smooth muscle
bind to dense bodies. during contraction, don’t move as much causing a squishing and rotation movement. useful for diameter changing in tubes.
Nervous tissue subdivisions
CNS: brain, spinal cord, optic nerve
PNS: all other nervous tissue, sensory and motor. info from CNS to organs and glands
Type sof nervous cells
neurons
neuroglia
Neuron
cell body with branched dendrites (receiver) and then axon (coated in myelin sheath) that sends info, branching into a terminal. high metabolic rate. electrical communication, no cell division
multipolar neuron
2 or more dendrites, and single axon. motor
bipolar neuron
one dendrite and one axon. branches between neurons and involved in special senses. cell body between axon and dendrite. relay info from receptor
unipolar neuron
dendrite and axon are continuous with cell body off to side
anaxonic
no differentiation between axon and dendrite, found in brain and sense organs, not well understood.
neuroglia
found in pns and cna. supportive cells, can divide, chemical communication. physical structure, repair, nutrient transport, regulate interstitial fluid
CNS neuroglia
astrocyte
oligodendrocyte
microglia
ependymal cell
astrocyte
star shaped, links to itself to form syncytium, support and communicate. maintain environment by regulating ions. blood brain barrier
oligodendrocyte
insulation, and forms myelin sheath that wraps around cns axons
Microglia
phagocytic. protection
ependymal cell
produce cerebrospinal fluid. nutrients and protections. have cilia and microvillia for CSF monitoring and movement
PNS neuroglia
schwann cell: pns oligiodendrocyte. that can also just support/surround non myelinated axons (one cell per axon)
satellite: surround neuron cell bodies. support fluid exchange
