Muscle Tissue Flashcards
what is muscle tissue specialised for
contraction in order to produce movement
what are the three types of muscle tissue
- skeletal
- cardiac
- smooth
muscle tissue is specialised to produce what
contractions
skeletal muscle tissue is regulated by which branch of the nervous system
somatic
what are the two branches of the peripheral nervous system
somatic and autonomic
what is the name of the outer connective tissue that encases entire muscles
epimysium
what is the epimysium
the outer connective tissue that encases entire muscles
what name is given to the connective tissue layer that surrounds bundles of muscle fibres known as fasicles
perimysium
what is the name given to the connective tissue layer that surrounds individual skeletal muscle fibres
endomysium
what are tendons
the strucutre formed by the coming together of the three connective tissue layers in skeletal muscle, at the tapering ends
what is acetylcholine
the chemical signal released at the neuromuscular junction
what are t tubules
the structural feature of skeletal muscle fibres that propagates action potentials into the interior of the cell
what is sarcoplasmic reticulum
the structural feature of skeletal muscle fibres that sequesters calcium away from myofibrils during relaxation
exlpain the structure and control of skeletal muscle
striated structure controlled by somatic nervous system
explain the structure and control of cardiac muscle
striated structure controlled by the autonomic nervous system
explain the structure and control of smooth muscle
non striated controlled by the autonomic nervous system
what is skeletal muscle
muscle tissue specialised for contractions that produce movement. it is attached to the skeleton and allows voluntary movement of the skeleton.
what are examples of subconscious movement of skeletal muscle
balance and posture
what is the structure of skeletal muscle fibres
- elongated, cylindrical cells with multiple peripherally located nuclei
- this is the main tissue type found within skeletal muscles
what is an individual skeletal muscle also classed as
an organ
which tissues are skeletal muscles composed of
skeletal muscle tissue, nervous tissue, blood vessels, connective tissues
what are fasicles wrapped by
perimysium
where is endomysium found
between individual muscle fibres
what are individual muscle fibres separated by
endomysium
what is fasciculi
where the groups of muscle fibres are grouped together
is perimysium a loose connective tissue
yes
what is the entire muscle externally surrounded by
the dense connective tissue known as epimysium
where are blood vessels and nerves found within the skeletal muscles
spread throughout the connective tissues coating the muscles
what is the skeletal muscle cell structure specialised for
contraction
what gives rise to the striated structure of skeletal muscle fibres
arrangement of myofibrils
what are myofibrils composed of
repeating protein units called myofilaments
what are the two myofilaments
myosin and actin
how is myson and actin differentiated
actin is light and myosin is dark coloured
where are the actin bands bisected by
dense Z lines
what do Z lines divide each myofibril into
contractile units called sarcomeres
what are sarcomeres
the contractile units of skeletal muscles
what is the contractile unit of skeletal muscle
sarcomeres
what do sarcomeres contract by
sliding filament mechanism
what causes contraction
a conformational changes causes the filaments to slide over each other and cause the sarcomere to shorten
what type of neurons innervate skeletal muscle
somatic motor neurons
how many muscle fibres do individual motor neurons innervate (supply with nerves)
several
what is a motor unit
a single motor neuron together with all the muscle fibres it innervates
how is action potential stimulated in muscle fibres
- neuronal action potential is converted to a chemical messenger known as acetylcholine at neuromuscular junction
- this is detected by receptors on muscle fibres
- stimulates action potential in muscle fibres
what is the sarcolemma
the membrane that invaginates into the sarcoplasm to form membranous t tubules
what is the sarcoplasmic reticulum
modified smooth ER. calcium ions are concentrated within it
what two features support the contraction of sarcomeres
sarcolemma and sarcoplasmic reticulum
what is the function of cardiac muscle
muscle found in the heart and is speciailsed for continuous autonomous contractions. pumps blood through the cardiovascular system
what is the structure of cardiac muscle like
elongatede branched cylindrical cells, with one or two centrally located nuclei. striated structure
what are the three layers to the heart wall
pericardium, myocardium, endocardium
what is the pericardium
the outer supporting tissue layer of the heart wall
what is the myocardium
cardiac muscle tissue within the heart wall
what is the endocardium
the single layer of endothelial cells found on the heart wall as the innermost layer
what is the histological structure of cardiac muscle
branched structure of individual cardiac muscle cells with a reticular connective tissue supporting a rich capillary network. specialised intercellular junctions known as intercalated discs that anchor cardiac cells together
what are the similarities with skeletal muscles and cardiac muscles
- identical arrangements of sarcomeres
- contains t tubules and sarcoplasmic reticulum
- numerous mitochondria
- glycogen and lipid granules
- contraction by sliding filament mechanism
what are the differences with skeletal muscle and cardiac muscle
- the autonomous contraction of cardiac muscles
- the sarcoplasmic reticulum slowly leaks calcium ions
- specialised cardiac muscles known as the conducting system
- intercalated discs that allow cardiac muscles to function as the synctium
what are the elements to the conducting system of the heart
- there is autonomous contraction initiated at the sinoatrial node
- the left and right atria contract
- atrioventricular nodde
- atrioventricular bundles
- purkinje fibres
- cardiac muscle fibres
what is the rate of inherent rhythm modulated by
autonomic nervous stimulation and hormonal stimulation
what is the function of smooth muscle
specialised for continuous contractions - typically to propel lumen contents (peristalsis)
where is smooth muscle found
lining hollow organs
what is the structure of smooth muscle
elongated, spindle shaped cells with tapered ends. single centrally located nuclei.
why is smooth muscle not striated
lack of sarcomeres
what is the gastrointestinal tract
a muscular tube lined by a mucous membrane
two muscle layers at the right angles
what is peristalsis
movement of the food through the gastrointestinal tract
what is the anatomical arrangement of the gastrointestinal tract specialised for
peristalsis
what are the different layers of the gastrointestinal tract
inner circular layer which constricts the lumen diameter
outer longitudinal later that shortens length
what modulates the intensity of peristalsis
the parasympathetic NS
what are the smooth muscle layers of the bowel wall called
- inner circular layer
- outer longitudinal layer
- parasympathetic ganglia
how are actin and myosin arranged in smooth muscle
a criss cross lattice
how is smooth muscle anchored to the cytoplasm and cell membrane
caveoli (invaginations of the membrane)
what is the structure of smooth muscle when in a relaxed state
elongated
are there striations in relaxed smooth muscle cells
no
