Human Anatomy Analysis - Essay Example

Specific tissue types and functions.

Tissue 1cTissue 1bTissue 1a

Tissue 1c:

This is cardiac muscle tissue.

Function;

It makes up the heart tissue. Individual cardiac muscle cells make up a syncytium that acts as a tubular pumping organ for blood. In mammals, it is single and four-chambered.

Tissue 1b:

This is smooth muscle tissue.

Functions;

These cells are slow contracting, and are responsible for involuntary visceral contractions such as peristalsis, bristling of skin hair (erector pili), uterine contractions, bladder contraction, and vasoconstriction.

Tissue 1a:

This is skeletal muscle, otherwise known as striated muscle.

Function;

This muscle type is abundant and responsible for the voluntary movement of the skeletal system. An example is a walking movement.

Definition of terms.

The definition of a muscle twitch is a contraction of a muscle in response to a stimulus that causes an action potential in one or more muscle fibers. It may also refer to Fasciculation. This is the involuntary contraction of a muscle, or muscle group associated with a neuron. They arise as a result of the spontaneous depolarization of a lower motor neuron (LMN), leading to the synchronous contraction of all of the skeletal muscle fibers associated with the motor unit. They may be deep or superficial. They are often benign, but maybe a sign of Rabies, Magnesium deficiency, Poliomyelitis, Organophosphate poisoning, or Isaac’s syndrome (Neuromyotonia).

This is the biochemical breakdown of glucose into pyruvate (2) for the eventual manufacture of ATP; the main energy currency for all cellular functions. It takes place in 10 steps. It has two main phases;

• The Preparatory Phase - in which ATP is consumed and is also known as the investment phase
• The Pay Off Phase - in which ATP is produced.

1. Isotonic contraction

This is a muscle contraction with sustained power output, but reduced muscle length (contraction of sarcomere). It is basically defined as the same tension contraction. There are two main types;

• Concentric

These are contractions that cause the muscle to shorten as it contracts. These are the most common types of contractions in daily life. An example is the contraction pattern of biceps brachii when lifting a book.

• Eccentric

They are less common. They involve muscle lengthening as it contracts. This is to facilitate a deceleration function of an opposing muscle group. An example is when walking or more appropriately when kicking. The quadriceps contract concentrically, while the hamstrings contract eccentrically to decelerate and help modulate the action.

1. Muscle flex

This is the action of contraction of a muscle to reduce its total length. An example is the lifting of a book. The biceps brachii has to flex to perform the action.                                                                  

I.M injection sites.

These are injections given directly into muscle. Generally, there are four main sites; the arm (deltoid), thigh (vastus lateralis), upper outer posterior buttock (gluteus maximus)-also referred to as the dorsogluteal site, and the lateral hip (gluteus medius) that is also called the ventrolateral site. Substances given via this route include morphine, codeine, streptomycin, and penicillin.

Acetylcholine receptors in skeletal muscle.

The receptors in muscle are found on the neuromuscular junction, or otherwise known as the endplate. The Ach receptors are of two types: Muscarinic and Nicotinic. Nicotinic receptors can be opened not only by acetylcholine but also by nicotine, hence the name "nicotinic” (Purves). The nicotinic type is the one found in the NMJ. The subtypes are N1 or NM receptors: these receptors are located at the neuromuscular junction. Acetylcholine receptors of the NM subtype are the only acetylcholine receptors that can be found at the neuromuscular junction.