Birds and mammals have a complete anatomical and functional seperation of oxygenated and deoxygenated blood flow through the heart. in mammalian heart systemic blood enters the right atrium and then passess through a membranous right atrioventricular valve into the right ventricle . Blood is ejected through the pulmonary semilunar valves via the left and right pulmonary arteries for oxygenation in the lung. The cardiac cycle of the mammalian heart consists of an atrial contaction (systole) and then refilling (diastole), coordinated with a ventricular systole and diastole.
effects of aging on skeletal muscle
Reduced muscle mass
increased time for muscle contract in response to nervous stimuli
reduced stamina
increased recovery time
loss of muscle fibers
decreased density of capillaries in muscle
muscle metabolism
The source of energy ATP, Kreatin phosphate. Anaerobic and aerobic respiration. Glycogen. ATP provides immediate energy for muscle contractions from 3 sources. Creatine phosphate. During resting conditions stores energy to synthesize ATP. Anaerobic respiration: occurs in absence of exygen and results in breakdown of glucose to yield ATP and lactic acid. Aerobic respiration: requires oxygen and breaks down glucose to produce ATP, carbon dioxide and water. more efficient than anaerobic.
What is atrophia?
After parturation, no mitosis occur in muscle tissue. Motor neuron connection to the muscle cell maintain muscle liveliness. Disconnection of motor neuron from muscle cells lead to the degeneration of the muscle cells. That is atrophia.
what is fatigue
Decreased capacity to work and reduced efficiency of performance. Types: psychological, depends on emotional state of individual. Muscular : results from ATP depletion. Synaptic: occurs in neuromuscular junction due to lack of acetylcholine.
molecular mechaniism of contraction
- Stimultion of muscle cells.
- cross bridge
- filament sliding
- ATPase activity of Myosin head
- Troponin-Tropomyosin action
- Attachment and detachment of the myosin head
- calcium and Mg+2 is required for contraction
- Myosin head ATPase activity is Ca+ dependent
- Release of Ca+ from sarcoplasmic reticulum
sarcomere shortening
The vertebrate and invertabrate animals muslce has similar structure and function. There are various type of muscle cells. 1. Striated muscle: it can be divided into skeletal and cardiac mucsle. Although the structure are similar in the skeletal and cardiac muscle, contractile activity is different. Skeletal muscle is usually under voluntary control. Cardiac and smooth muscle are involuntary muscle. Innervation of both smooth and skeletal muscle are different.http://muscle-biology.blogspot.com/
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