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Created by laurenwalker_02
over 9 years ago
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Question | Answer |
What are the three types of muscles? | Striated muscle Smooth muscle Cardiac muscle |
Describe Striated muscle | Also known as skeletal/ voluntary muscle and is attached the skeleton involved in movement Contracts rapidly and fatigues quickly Is striped under a microscope Under the control of the voluntary nervous system |
Describe smooth muscle and where it is found | Smooth muscle is found in the gut and in blood vessels It contracts slowly and fatigues slowly Its under the control of the involuntary nervous system Not striped under a microscope |
Describe Cardiac Muscle | Is found only in the heart It contracts spontaneously and never fatigues It is striated and fibres are joined by cross connection |
What are muscle fibres made up of ? | Made up of myofibrils lying parallel to each other that contain individual units called the sarcomere. The sarcomere is made up of proteins actin and myosin. The myofibrils cytoplasm is called the sarcoplasm and contains many mitochondria and there are a network of membranes running through called sarcoplasmic reticulum to store and release calcium ions |
What is myoglobin? | Found in muscle cells, its like haemoglobin but has one chain instead of four. It has a higher affinity of oxygen so takes up oxygen readily |
What are slow twitch fibres? | Also known as oxidative or red muscle fibres Adapted for steady action over a period of time and maintain body posture Contract slowly and stay in tetanus Has rich blood supply Lots of mitochondria Lots of myoglobin Rely as glucose as a fuel supplied by blood vessels to continue to produce ATP. |
What is fast twitch muscles fibres? | Often known as white or glycolytic fibres Contract rapidly suitable for sudden bursts of activity Often function anaerobically because fatigues quickly Low mitochondria and low myoglobin Contains many myofibrils packed in contain rich glycogen stores to convert to glucose Contain relatively high levels of creatine phosphate use to form ATP from ADP |
What is myosin made up of? | Myosin is made up of two polypeptide chains wrapped around each other. Each ending in large globular bounded with ADP an inorganic phosphate A myosin filament is made up of many of these bundled together |
What is Actin made up of? | Actin filament made up of two chains of actin monomers joined together like beads on a necklace Actin provides the binding sites for myosin to join Tropomyosin is wrapped around the actin filament and when relaxed it covers myosin bonding site Tropomyosin has troponin attached. |
Draw a sarcomere when relaxed and contracted | |
Explain the Sliding Filament Theory | 1) Calcium ions bind to troponin and changes shape, pulling tropomyosin, exposing myosin binding sites 2) Myosin head binds to binding sites forming an actomyosin bridge 3) ADP and Pi are released from myosin head, causing it to change shape 4) Myosin head bends forwards, pulling the actin filament along myosin, shortening sarcomere 5) Free ATP binds to head, breaking the bond between actin + myosin 6) Activates ATPase in myosin head 7) Hydrolyses ATP, which provides energy needed to return myosin head 8) Calcium ions get pumped back into sarcoplasmic recticulum if not stimulated again 9) Troponin and tropomyosin returns to normal 10) Muscle fully relaxed |
Tissues of the Skeletal Systems: Describe bone properties and what is made up of. | Bone is made up of bone cells embedded in a matrix of collagen and calcium salts Bone is strong under compression Is relatively light, but is strong and hard |
Tissues of the Skeletal Systems: Cartilage. | Cartilage is hard and flexible Made up of cells called chondrocytes within organic matrix Cartilage is elastic Able to withstand compressive forces Good shock absorber Found between bones |
What are the two types of Cartilage? | 1)Hyaline: found at the end of bones and in nose, air passageways and parts of the ear) 2) White Fibrous Cartilage: Found between bones and in the joints great tensile strength + less flexible Made of bundles of densely packed collagen in the matrix |
Tissues of the Skeletal Systems: What are tendons? | Tendons join the muscle to the bone Made up entirely white fibrous tissue and consists of bundles of collagen fibres Provides little shock absorption for when muscle overstretches |
Tissues of the Skeletal Systems: What are ligaments? | They hold bones together + keep them in correct alignment Found both around joint as a capsule and within joint itself Made up of yellow elastic tissue for strength + elasticity |
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