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Micardis

By E. Mamuk. Northwest College of Art.

Calcium enters a cardiac muscle cell during the plateau of lengths somewhat less than the optimal length for peak the action potential 40mg micardis fast delivery. This entry promotes the release of in- force production, facilitating length-dependent regulation ternal calcium stores, which are located mainly in the sar- of the muscle activity. A typical cardiac muscle contraction produces less than active transport systems remove calcium from the maximal force, allowing physiologically regulated changes cytoplasm. Cardiac muscle derives its energy primarily from the to the body’s current needs. It has very little capacity for anaerobic muscle is inversely related to the force being exerted, as metabolism. The tissue is striated in appearance, as in skeletal muscle, and the structural characteristics of the sarco- The heart is composed of several varieties of cardiac mus- meres and myofilaments are much like those of skeletal cle tissue. The regulation of contraction, involving calcium ocardium, so named for their location, are similar struc- control of an actin-linked troponin-tropomyosin com- turally, although the electrical properties of these two areas plex, is also quite like that of skeletal muscle. The mechanical properties of car- of action potentials, and their contractile ability is greatly diac muscle relate more closely to those of skeletal mus- reduced. Finally, there are the highly specialized tissues of cle, although the mechanical performance is considerably the sinoatrial and atrioventricular nodes, muscle tissue more complex and subtle. This arrangement aids in the that follow refer primarily to the ventricular myocardium, spread of electrical activity. Cardiac myocytes have a sin- the tissue that makes up the greatest bulk of the muscle of gle, centrally located nucleus, although many cells may the heart. The cell membrane and associated fine connective tissue structures form the sarcolemma, as in skeletal muscle. The sarcolemma of cardiac muscle sup- Cardiac Muscle Cells Are Structurally ports the resting and action potentials and is the location of ion pumps and ion exchange mechanisms vital to cell func- Distinct From Skeletal Muscle Cells tion.

Evolution of the Brain 15 3 2 1 3 1 2 4 4 Frog Crocodile 3 1 1 2 2 4 Hedgehog A Evolution of the vertebrate brain Lemur (bush baby) Gorilla Homo pekinensis Neanderthal Cro-Magnon B Endocranial casts of a gorilla and of fossil hominids C Endocranial casts of Homo sapiens order 20mg micardis mastercard, lateral view and basal view Kahle, Color Atlas of Human Anatomy, Vol. Basic Elements of the Nervous System The Nerve Cell 18 The Synapse 24 Neuronal Systems 32 The Nerve Fiber 36 Neuroglia 42 Blood Vessels 44 Kahle, Color Atlas of Human Anatomy, Vol. Some have short axons (interneurons), others have axons more than 1 m long (pro- The nervous tissue consists of nerve cells jection neurons). Blood vessels and meninges do different methods yield only partial images not belong to the nervous tissue; they are of of neurons. The nerve cell (gan- method) shows nucleus and perikaryon glion cell or neuron) is the functional unit (B –D). In its mature state, it dendrites, is filled with clumps (Nissl sub- is no longer able to divide, thus making pro- stance, tigroid bodies) and may contain pig- liferation and the replacement of old cells ments (melanin, lipofuscin) (D11). Motor neurons possess a large peri- and one main process, the axon or neurite karyon with coarse Nissl bodies, while (A–D3). The perikaryon is the trophic center of the cell, and processes that become separated Impregnation with silver (Golgi’s from it degenerate. It contains the cell nu- method) stains the entire cell including all cleus (A4) with a large, chromatin-rich neuronal processes; the cell appears as a nucleolus (A5) to which the Barr body (sex brown-black silhouette (B–D). The processes of other neurons often end at small dendritic appendices, spines (thorns), which give the dendrites a rough appearance (D). The axon conducts the nerve impulse and begins with the axon hillock (AD7), the site wherenerveimpulsesaregenerated. Atacer- tain distance from the perikaryon (initial segment) it becomes covered by the myelin sheath (A8), which consists of a lipid-con- taining substance (myelin). The axon gives off branches (axon collaterals) (A9) and fi- nally ramifies in the terminal area (A10) to end with small end-feet (axon terminals, or boutons) on nerve cells or muscle cells. The bouton forms a synapse with the surface membrane of the next cell in line; it is here that impulse transmission to the other cell takes place.

In fact cheap micardis 40 mg line, the term skeleton comes from a Greek word meaning is the axial component. It performs many body functions, including move the brachium (arm) and antebrachium (forearm). The skeleton forms a rigid framework to which bones, and the phalanges (“finger bones”) of the hand. The two ossa coxae (“hipbones”) are the of interest that the skeleton’s 206 bones support a mass of appendicular components of the pelvic girdle, and the muscles and organs that may weigh 5 times as much as the sacrum is the axial component. The pelvic girdle supports the weight of the brain and spinal cord; the rib cage protects the heart, body through the vertebral column and protects the viscera lungs, great vessels, liver, and spleen; and the pelvic girdle within the pelvic cavity. Each lower extremity contains a where blood cells are produced are protected within the proximal femur (“thighbone”) within the thigh, a tibia spongy bone tissue of certain bones. Bones serve as anchoring attachments metatarsal bones, and the phalanges (“toe bones”) of the for most skeletal muscles. It takes place in tissue Knowledge Check called red bone marrow located internally in some bones 1. In an infant, the spleen and liver produce red which are bones of the axial skeleton and which are bones blood cells, but as the bones mature, the bone marrow of the appendicular skeleton. Describe the locations and functions of the pectoral and ond by the red bone marrow to replace those that are worn pelvic girdles. Lipid is stored in the adipose tissue within the medullary cavity of certain bones. The adipose tissue and its lipid content are known as yellow bone marrow (fig.


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