P4 – Describe the three structures of the skeletal muscle (Epimysium, Perimysium and Endomysium) There are three structures of the skeletal muscle: Epimysium is a thick layer of irregular connective tissue that pulls the entire muscle as well as protecting the muscle from friction that may be caused by other muscles and bones surrounding them. Also, it is the fibrous tissue which covers and surrounds skeletal muscles. The Epimysium carries on past the end of bones in order to create muscle tendons. Perimysium surrounds a bundle of muscle fibres, it is a casing of connective tissue. Endomysium is found within a muscle and it contains nerves and capillaries.
Isotonic contractions are ones where the muscle is caused to change length when it contracts and there is movement of a part of the body. Concentric contractions are the ones where as the muscles shortens there is tension so the muscle increase in size, for example picking up a weight. Eccentric contractions are the ones
Acetylcholine then binds to receptors on the muscle fibre membrane (sarcolemma) causing depolarisation. A wave of depolarisation travels down tubules (T system). T system depolarisation leads to Ca2+ release from stores in sarcoplasmic reticulum. Ca2+ binds to proteins in the muscle, which leads to contraction. Acetylcholinesterase in the gap rapidly breaks down acetylcholine so that contraction only occurs when impulses arrive continuously.
After their job is accomplished, the osteoclast undergo apoptosis. This process proceed to the reversal stage, during which coupling signals are sent to attract osteoblast into resorptive sites. Resorption is then turned off and the formation stage follows. The osteoclasts synthesize bone matrix and facilitate its mineralization. Calcium and phosphate ion are deposited into the matrix, leading to hardening of the bone.
As Angiotensin I flows through the renal and pulmonary circulations, a second enzyme called Angiotensin Converting Enzyme (ACE) cleaves Angiotensin I into Angiotensin II. Angiotensin II acts in three ways to conserve ECF volume. First, AT-II is a powerful vasoconstrictor. AT-II constricts the renal arteries and arterioles in order to increase perfusion pressure in the renal cortex where most glomeruli are located. Second, AT-II crosses into 2 areas of brain lacking the blood-brain barrier (the SFO- Subfornical Organ and OVLT – Vascular Organ of the Lamina Terminalis) to trigger the sensation of thirst.
The heart is covered by two-layered wall that form a sac which enclose it, and the space between the layers is filled with lubricating fluid to allow them to slide past each other. One full cardiac cycle takes about 0.8 second, so it needs a much specified tissues and cells to hold on this precise function (Campbell, 1977). The wall that enclose the heart is comprises of three layers. Outer pericardium is the very outer layer of the heart wall which consists of adipose and connective tissues and it functions reducing the friction to protect the heart. Epithelial and connective tissues form the endocardium which is the inner layer of the wall, it contains cardiac muscle fibers as well.
Myosin cross bridges stretches out from the thick fibers to re slim fibers. Very still, the cross bridges are not connected to actin. The cross-bridge heads capacity as ATPase enzymes. ATP is split into ADP and Pi enacting the cross bridge. At the point when the actuated cross bridges connect to actin, they discharge Pi and experience a power stroke.
When the both sympathetic and parasympathetic ganglion direct to the same organ or gland the total function of the gland is carried by the input signals given by chain ganglia and the terminal ganglia. E.g. the sympathetic ganglion can increase the heart rate and the parasympathetic ganglion can decrease the heart rate. Terminal ganglia in the sympathetic nervous system receive impulses from the head, neck, thoracic and lumber regions. Terminal ganglia of the parasympathetic system receive impulses from the lower abdominal region as well as the pelvic cavity.
Stratum Lucidum III. Stratum Granulosum IV. Stratum Spinosum V. Stratum Basale 1.2.2. Dermis It is middle layer which contain connective tissue, sweat gland, hair follicles, collagen, blood vessels, nerves and various glands. Function of dermis layer is to provide strength, elasticity and to cushion the body stress and strain.
The brain sends an impulse to the muscle, which then travels down through the motor neuron to the neuromuscular junction, to which it then lets out acetylcholine. The impulse then travels through the sarcolemma and transverse tubules (T- tubules). While the impulse passes through the transverse tubules, the sarcoplasmic reticulum releases calcium
MUSCLE TYPES In the body, there are three types of muscle: skeletal (striated), smooth, and cardiac. Skeletal Muscle Skeletal muscle, attached to bones, is responsible for skeletal movements. The peripheral portion of the central nervous system (CNS) controls the skeletal muscles. Thus, these muscles are under conscious, or voluntary, control. The basic unit is the muscle fiber with many nuclei.