Week 4 Flashcards
How many muscles are in the body?
650
How many joints are in the body?
187
What are the three types of muscle
Cardiac, smooth and skeletal
Describe cardiac muscle
Small cells limited by ability to repair. Involuntary muscle contractions. Single nuclei
Describe skeletal muscle
Larger cells, can be 30cm long for one cell, can be repaired however forms scar tissue. Consciously contracts. Multiple nucleus
Describe smooth muscle
Single nuclei, can be repaired, involuntary contracts
What are the functions of muscle tissue
Produces body movement
Stabilises body positions
Regulates organ volumes - bands of smooth muscles called sphincters
Movement of substances within the body - blood, lymph, urine, food, fluid, sperm
Produces heat
Properties of muscle tissue
Excitability - respond to chemicals from nerve cells
Conductibility - propagate electrical signals over membrane
Contractability - short and generate force
Extensibility - to be stretched without damaging tissue
Elasticity - ability to return to original shape
What does muscle tissue look like
Striated with light and dark bands
Functions of skeletal muscle
Produces skeletal movement
Maintain body position
Support soft and hard tissues
Guard body openings
Maintain body temperature
Stores nutrient reserves
Proprioception
What are the three connective tissues found in skeletal muscle structures?
Epimysium - outerlayer - dense irregular CT - separates muscle from surrounding tissue, connect to deep fascia.
Permysium - middle layer - surrounds each muscle fibre cell. Contains blood vessels and nerve supply 50/50 collagen and elexistin
Endomysium - inner layer - surrounds individual muscle cells. Contains capillary and nerve fibres contracting muscle. Contains satellite cells
What makes a tendon or aponeurosis
Endomysium, permysium and epimysium come together at the end of muscles to form connective tissue attachments to bone matrix
Which connective tissues are nerves found in?
Perimysium and Endomysium
Messages reach the muscle via…
Peripheral nerve
A collection of muscle cells are supplied by…
A motor neuron
What makes a motor unit
One motor nerve and the muscle fibre it supplies
What supplies each muscle cell with a nerve signal
Terminal banco of a motor neurone
How many capillaries are a muscle cell in contact with
1 or 2
Where are nerve fibres and capillaries found?
Endomysium between individual cells
What is the role of the vascular system within the muscles?
To supply large amounts of O2
Supply nutrients
Carry away waste products; lactic acid, water and CO2
How are skeletal muscle cells developed?
Fusion of mesodermal cells called fibroblasts. Myoblasts flatten and fuse to become and immature muscle fibre. Then become mature
What shape are muscle fibres?
Long and cylindrical
What is the sarcolemma
The cell membrane, surrounds the sarcoplasma.
What is the sarcoplasma filled with?
Tiny threads called myofibrils and myoglobin
What is myoglobin
Red coloured o2 binding proteins
Where do transverse T tubules go?
Through the sarcolemma into the middle of the cell
What is the job of a transverse t tubules
Carry muscle action potentials down into the cell and allow the entire muscle fibre to contract simultaneously
What structure is a sarcoplasmic relictum?
Membranous structure
What is the job of sarcoplasmic relictum
Transmits action potentials to the mysofibrils. Forms chamber at each end (terminal cisternae) attached to the-tubules. Stores ca++ in relaxed muscle and releases ca++ which triggers muscle contraction
What is a triad made of?
1 t-tubules and 2 terminal cistine
How does terminal cisternae transmit ca++
Via ion pumps
What are muscles fibres filled with?
Myofibrils separated by sarcoplasmic relictum
What are the contractic proteins in the muscle called?
Myofilaments
What protein makes a thick myofilament
Myosin
What filament protein makes a thin myofilament
Actin
What is the pattern that is made in muscle fibres under a microscope?
Striatations
Why is the I band shown as lighter on a microscope?
Contains only thin filaments (actin)
What makes the A band
Mysoin
How many filaments overlap each other in the A band?
6 thin filaments surround each thick filament
What zone is in the middle
H zone
Which zone is at the end
Z
What are the 3 actions proteins in the muscle are responsible for
Contractile, regulatory and structural
What are the contractile proteins?
Myosin and actin
What are the regulatory proteins
Troponin and tropomyosin
What are the structural proteins
Titan, myomensin, nebulizar and dystrophin
How would you describe a myosin molecule
Like two golf clubs twisted together.
Where do the myosin heads extend towards?
The thin filaments and are led in place by the M line
What covers he binding site on an Actin molecule?
Tropomyosin
What lines make up a sarcomere
One z line to another
Which muscle contraction is Titin important in?
Eccentric isometric movement
What anchors thick filaments tot he M and Z line
Titin
How many times can the portion of the sarcomere from the Z line to the end of the thick filament stretch?
4 times
What protein transmits tension to the tendon
Dystrophin
What helps align the thin filaments
Nebulizo
