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/
organization 3
Connective tissue, nerve, blood vessels. Connective tissue, external lamina, endomysium, perimysium, fasciculus, epimysium. Fascia, nerve and blood vessels, abundant.
properties of muscle
contractility: ability of a mucle to shorten with force. Excitability: capacity of muscle to respond to a stimulus. Extensibility : muscle can be streched to its normal resting lenght and beyond to a limited degree. Elasticity ability of mucle to recoil to original resting lenght after stretched.
Muscular System Structure and Function presentation video
another great video from youtube about muscle system. An overview of the main structures of the Muscular system in human body. Muscular System Structure and Function presentation video.
Muscle Driven video
A Three-Dimensional Muscle-Driven Simulation of Running from youtube. This is the first three-dimensional, muscle-driven simulation of a full running gait cycle. Muscle are represented by lines, which change from blue to red as the muscle activates.
sympatric speciation
Original population occupies a homogenous habitat. Climate change and other factors form two distinctly different habitats that are still physically part of the same general region. There are no barriers to movement between habitat.Different environment in the two habitat lead to genetic divergence of organisms living in each. biology
allopatric speciation
allopatric speciation in which two populations are geographically seperated from one another. Sympatric speciation in which two populations share the same geographical area. biology
isolation from gene flow is the key to both allopatric speciation and sympatric speaciation. Allopatric speciation can occur in population that are physically separeted. Sympatric speciation can occur in populations that live in the same area.
species and speciation
Biologist define species as groups of actually or potentially interbreding natural populations which are reproductively isolated from other such groups. This definition known as the biological species concept.
how do new species form: speciation depends on two factors: the isolation and the genetic divergence of the population. Isolation of populations and genetic divergence.
genetic drift
Genetic drift is one of the major mechanism of evolutionary change and has significant implications for human interactions. Different form of the same gene are known as alleles. A population is all the individuals of a species living in a particular place at a particular time. the relative proportion of an allele in a population is the allele frequently. The sum of all genes in a population is the gene pool. Hardly weinberg equilibrium is the maintained of a population is not evolving. The alleles responsible for blue color has ben lost, such loss of alleles is usually consequence of genetic bottleneck. Population bottleneck can cause all of the following except: changes in allele frequency. Loss of alleles. Reduction in genetic variability. Bottleneck happens to small population. The effects on evolution change are random. There is a loss of genetic variation after a bottleneck in our example. The allele for blue coloration was lost.
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