What are the functions of the muscular system?
- Produce skeletal movement
- Maintain posture and body position
- Support soft tissue
- Guard entrances and exits
- Maintain body temperature
- Store nutrients
What are the three types of muscle and state some facts?
- Muscular system consists of three muscle types: cardiac, smooth, and skeletal
- Skeletal muscle most abundant tissue in the human body (40-45% of total body weight)
- Human body has more than 430 pairs of skeletal muscle; most vigorous movement produced by 80 pairs
What are the location, function, appearance and control of the skeletal muscle?
- Skeleton
- Movement, Heart and Posture
- long and thin contractile fibres that are striated (due to thick and thin filaments), multi-nucleated, parallel fibres
- voluntary
What are the location, function, appearance and control of the Cardiac muscle?
- Heart
- Continually pumps blood
- striated, one central nucleus
- involuntary
What are the location, function, appearance and control of the Visceral muscle?
- G.I tract, uterus, eye, blood vessels
- peristalsis, blood pressure, pupils size, erect hairs
- no striations, one central nucleus
- involuntary
how does the skeletal muscle attach to the bone?
- origin - Attachment to the more stationary bone by tendon closest to the body or muscle head or proximal
- insertion - attachment to the more moveable bone by tendon at the distal end
- During movement, the origin remains stationary and the insertion moves.
- As one group of muscles contracts, the other group stretches and then they reverse actions.
list the organisation of the muscle tissue
Skeletal muscle, bundle of muscle fibres (fascicles), muscle fibre(cell, made from myofibrils), myofibril (made up from thick and thin filaments).
What are the 4 different types of connective tissue?
- Deep fascia: Surrounds entire skeletal muscle and extends beyond its length.
- Epimysium: Closely surrounds skeletal muscle, binds fascicles together.
- Perimysium: Surrounds each fascicle (bundle of fibres).
- Endomysium: Surrounds each muscle fiber (cell).
What is the fascia?
- Surrounds an individual skeletal muscle, separating it from other muscles
- Fascia may extend beyond the ends of the muscle to become a tendon
- Fascia may connect muscle to muscle and is called an aponeurosis
Sarcomere
- The length of each myofibril is divided into repeating units called sarcomeres
- A sarcomere is the functional unit of skeletal muscle
- Sarcomere exists from Z-line to Z-line
- A-Band is dark middle band (Overlapping think & thin filaments)
- I-Band – ends of A-Band, thin filaments only
- Z-line is in the middle if the I-Band
Neurons
- Highly specialised
- Some of the longest lived cells in your body
- Irreplaceable
- Amitotic – Lose their ability to divide
- Have huge appetites (25% of calories)
- Share the same basic structure
Glial Cells
- Many different types
- Many different functions
- Outnumber neurons by about 10:1
The Central Nervous System
- The central nervous system consists of the brain and the spinal column.
- The brain sorts out sensory information and gives orders. It is responsible for all complex functions.
- The spinal cord conducts two way signals between the brain and the rest of the body. Also responsible for reflexes.
Where is the sarcomella?
It is in the muscle fibre, the layer under the endomysium
Describe the overview of the nervous system
Central Nervous System and Peripheral Nervous System. Peripheral contain Sensory Division (afferent) and Motor Division (efferent). Motor Division contains Somatic (voluntary) and Autonomic (involuntary) Nervous System. Autonomic splits into Sympathetic (fight or flight) and Parasympathetic (rest and digest)
Name some glial cells in the CNS
Ependymal (line cavities), Oligodendrocytes (wrap and insulate, form myelin sheath), Astrocytes (support, regulate ions), Microglia(defend)
Name some glial cells in the PNS
Satellite cells (surround neuron cell bodies), Schwann Cells (insulate, form myelin sheath)
Describe the basic structure of neurons
Dendrites(input), then soma (cell body), then Axon (transmission line), then Axon terminals (outputs)
Describe the different types of neurons
Bipolar (interneuron), Unipolar (Sensory neuron), Multipolar (Motor neuron), Pyrimidal cell
What is the diameter of a muscle fibre?
40-100um
