Verified Document

Muscular System The Normal Anatomy And Physiology Essay

Related Topics:

¶ … Muscular System The normal anatomy and physiology of a muscle determines its capability of formulating a contraction. The contraction of a muscle is dependent on the ability of a neuron to become excited through a process that includes a concentrated flow of sodium (Na+), potassium (K+), and calcium (Ca+) through the neuron and eventually into the muscle cell (Tortora & Derrickson, 2011). A neuron begins its resting membrane potential at -70mv. In order for an action potential to occur, which is the event that will precede the muscle contraction, the membrane must first depolarize and become more positive, reaching -55mv. Once -55mv is reached, the membrane is said to be at the threshold potential, the voltage by which most Na+ channels in the cell membrane would open. After the first Na+ channel opens, the cell becomes even more depolarized and Na+ ions move into the cell (Martini, Nath, & Bartholomew, 2011).

As further depolarization is occurring, more Na+ channels open along the neuron causing the one following it to open, but making the ones behind it that already are open completely unable to perform any activity. Eventually the part of the neuron where the action began reaches a level of 0mv to +30mv, a range where K+ channels can open (Tortora & Derrickson, 2011). The same process occurs concerning the K+ channels as with the Na+ channels, allowing K+ back into the cell, until the cell completely hyperpolarizes, reaching -70mv and ending the action potential, with the mobile Na+ and K+ ions transitioned back to their respective spaces by the sodium-potassium pump (Tortora...

As the process described already, the signal proceeds down multiple neurons to the skeletal muscle in the legs, those muscles are depolarized, but this time to allow for the opening of Ca+ channels. The release of calcium ions at the neuromuscular junction between the neuron and the skeletal muscles leads to vesicles containing acetylcholine to be released and those will travel to the plasma membrane and exocytose, releasing the acetylcholine into the synaptic space between the cells (Martini, Nath, & Bartholomew, 2011). Acetylcholine binds to ligand receptors on the skeletal muscle membrane, opening and allowing Na+ ions to flow into the cell. The depolarization and generation of an action potential occurs as the cell membrane reaches threshold. The action potential is fully propagated as voltage-gated Na+ channels open and Na+ ions flow into the cell, and cell communication continues throughout the skeletal muscle (Martini, Nath, & Bartholomew, 2011).
During the process of the action potential flowing through the skeletal muscle, Ca+ channels in the sarcoplasmic reticulum open to allow the flow of Ca+ which bind to Troponin C, a protein linked to tropomyosin, both of which are associated overarchingly with actin (Martini, Nath, & Bartholomew, 2011). The binding of Ca+ to troponin C. causes a conformational change in the protein, moving tropomyosin away from the actin-myosin binding site. Without tropomyosin, myosin is free to bind to actin, and can…

Sources used in this document:
References:

Chabner, D. (2011). The language of medicine and companion cd. (9 ed.). Saint Louis: WB Saunders Co.

Martini, F., Nath, J., & Bartholomew, E. (2011)..Fundamentals of anatomy and physiology. (9th ed.). San Francisco: Pearson Benjamin Cummings.

Tortora, G.J., & Derrickson, B.H. (2011). Principles of anatomy and physiology. (13th ed., Vol. 22). Hoboken, New Jersey: Wiley.
Cite this Document:
Copy Bibliography Citation

Related Documents

Muscular System and Exercise the
Words: 1132 Length: 4 Document Type: Essay

Disuse atrophy of the muscles is caused by prolonged inactivity, which often occurs after sustaining an injury. Hypertrophy of the muscles is achieved through regular diet and exercise. 1(p127) Two types of training, strength and endurance, greatly increase muscle condition. Strength training increases muscle condition through the use of resistance. While conditioning through resistance will increase the number of myofilaments in muscle fiber and increases muscle size, it will

Anatomy and Physiology Organ Systems
Words: 925 Length: 3 Document Type: Essay

However, all muscles are ultimately controlled by the central nervous system. Because the muscles are attached to the skeleton, all skeletal movements can be traced back to the central nervous system. The integumentary system is one of the body's primary interfaces with the outside world. Together with the sensory system, the integumentary system interact with the central nervous system by communicating its inputs. 3. Homeostasis is the body's state of

Physiology Structure of the Nervous
Words: 2520 Length: 8 Document Type: Research Paper

These indications then proceed to the neuromuscular connections of skeletal muscles. From there, acetylcholine is released from the axon terminal knobs of alpha motor neurons and received by postsynaptic receptors of muscles, thereby communicating the stimulus to contract muscle fibers (Ihlen & Vereijken, 2010). Psychological Influences Research on patient's brains scanned by Positron Emmision Tomography have designated that the kind of thoughts people have influence the balance of brain chemicals, so

Anatomy and Physiology of Tetanus
Words: 2152 Length: 7 Document Type: Research Paper

). These complications will be discussed in the discussion section of this paper. Discussion Taking into account the physiological functioning of these bacteria on the human sensory and muscles muscle system it becomes clear that that this can be a serious threat to human health and, as discussed above, this disease can lead to death. Modern medicine has however created an antidote to the effects of this disease. Tetanus can be prevented

Main Systems of Human Body
Words: 3828 Length: 12 Document Type: Essay

The circulatory or cardiovascular system is responsible for moving nutrients, wastes and gases between body cells, transporting blood across the whole body and battling disease (Circulatory System). Its principal elements are the heart, numerous blood vessels, and blood. The heart forms the circulatory system's core. This 2-sided, 4-chambered pump which distributes blood to various arteries comprises of the right and left ventricles, and right and left atria. The ventricles, situated within

Heart Identify the Basic Anatomy
Words: 756 Length: 3 Document Type: Essay

(Ibid). Identify all components of a normal ECG rhythm- a typical, or normal ECG tracing of the heartbeat consists of a P. wave, a QRS complex, a T. wave and a U. wave (visible in 50-75% of cases). Identify basic ECG rhythms -- ECG rhythms are printed on graph paper, the smaller squares represent .04 second; 1 second 25 small squares, etc. The basic rhythms are: (Source: ECG Tutorial, 2006). Identify basic dysrhythmias

Sign Up for Unlimited Study Help

Our semester plans gives you unlimited, unrestricted access to our entire library of resources —writing tools, guides, example essays, tutorials, class notes, and more.

Get Started Now