Muscle tissue

• What are the main functions of muscles (5)

  They help with movement , generation of heat , the movement of fluid or food they help propel for example the stomach and heart muscles moving blood.They impact the organ volume e.g how much an organ can stretch to accommodate food for example and muscles can provide protein supply , if the body doesn't get enough protein from food the muscles will start to breakdown.
• What makes muscle different to other Tissue ?

  The main role is contractibility , however like nervous tissue it can become excitable in repots to stimuli and it has a close relationship with connective tissue(forms the sheath around muscle fibres - perimysium ) muscle tissue must be able to stretch hence its extensible and elastic. extensible means it can stretch without damage
• What are the three different types of muscles ?

  Cardiac , smooth and skeletal \
• what is the shape of skeletal , cardiac and smooth muscle ?

  skeletal is long and cylindrical like a pack of straws. Where as cardiac is also cylindrical but its branched and smooth muscle is a fusiform shape.
• Describe the nucleus of each muscle cell ?

  Cardiac muscle has one centrally located nucleus like smooth muscle however skeletal muscle has lots of peripherally located nucleus around the edges of the cell.
• What is the role of intercalated disks and what type of muscle are they found ?

  Intercalated disks are found in cardiac muscle they are a group of contractile proteins , with small gaps in between.These help with contractility and action potentials.
• What are the striations of each muscle type ?

  Smooth is not striated that's why it's called smooth muscle however cardiac and skeletal are striated.
• What is the location of each type of muscle ?

  Cardiac muscle is found in the heart , smooth m muscle is found in the walls of visceral organs like the bladder the eye , the blood vessels and skin. Skeletal muscle is attached to bones on the skeleton.
• Explain some of the cardiac muscle roles and preterites ?

  Cardiac muscle is found in most of the walls of cardiac muscle , cardiac muscle makes up the heart which is necessary to pump blood around the heart hence it must be able to contract and relax this must be done invoiluntary without any input this is done through a built in pacemaker and autorhymically which means the heart consoles how it beats , however there are other inputs that contribute to the strength and speed of heart contractions which can be from the endocrine system e.g hormones or the nervous system e.g neurotransmitters.
• What are the main qualities of smooth muscle and the functions - can compare to heart ?

  Like cardiac muscle smooth muscle doesn't require voluntary input its classified as involuntary. Meaning it also has some autorythmically for movements. Again like cardiac muscle it can be controlled / affected by the endocrine system and nervous system. Specifically the ANS. However unlike cardiac smooth muscle is non striated.
• What is an example of smooth muscle that is involuntary and has auto rhythmically ?

  GI tract
• What is the fascia and what is its function ?

  The fascia is a layer of connective tissue that acts as sheaths separating muscle fibres attaching them to tendons to stabilise. However its also involved in the overextension and transmission of tension
• What are the layers of the skeletal muscle ?

  The first layer is the epimysium ,then there are bundles of muscle fibres known as fascicles wrapped in the perimysium.Within the perimysium these individual fibres are then bundled by the endomysium.
• Describe the structure of a muscle fibre

  Skeletal muscle is created by myoblasts which fuse together to form fibrils. The skeletal muscle requires many mitochondria for energy to contract. It also has a sarcolemma (which is the plasma membrane for muscle cells ) the sarcoplasmic reticulum (similar to ER ) is essential for the contraction and relaxation of muscle through calcium
• Whats the advantage of having a lot of nuclei in the skeletal cell ?

  Ensures transcription and translation can be done at various points in the cell as the skeletal muscle cell is long hence need multiple nuclei for protein production.
• Describe the structure of a myofibril ?

  They have repeating units of protein called the sarcomere , this is made up of both thick and thin filaments which give skeletal muscle its striations. The thin filament its actin and the thick filament is myosin
• What is dark and light bands and what one is actin and myosin ?

  The thick dark band is myosin and the light thin band is actin
• Give an example of a disease of the muscle ??

  Neuromuscular disorders which impact any aspect of the motor unit either the neurone , the NMJ or the muscle itself .Example would include motor neurons disease.
• Give an example of metabolic myopathy in muscles ?

  Issues with the generation or storage of ATP either mitochondria or glycogen storage within muscles cells for energy . This results in fatigue due to lack of energy , weakness of muscles , cramps and pains .As a metabolic imbalance of ATP can can result in cramps as ATP is needed to detach actin and myosin heads for muscle relaxation.If there are low quantities muscle will not fully relax and stay partially contracted
• What are the three main symptoms of metabolic myopathy ?

  Fatigue , muscle weakness and cramps and pain
• When does muscle myopathy usually occur ?

  Onset of teenage years
• What are the two main things that impact muscle metabolic myopathy ?

  Glycogen storage and mitochondrial myopathies