Human Biological Science (Coordination and Control) (Essay Sample)

Human Biological Science (Coordination and Control)
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19 February 2014Human Biological Science (Coordination and Control)
Various processes take place in the human body. One of such processes is coordination and control. Without the process, it would be impossible for the human body to function properly. The paper seeks to have an overview in the process of coordination and control. As a result, at the end, it will be possible to differentiate, describe, locate, and explain some of the component and vital processes of the system.
TAQ1


The nervous system plays a crucial role in control and communication, in a living animal. The nervous system has various components. Each component plays its role in the system. The basic component of the nervous system includes the central and peripheral nervous system. The CNS constitutes of the spinal cord and brain. The brain and spinal cord are located inside the skull and vertebrae. The two parts play a significant role in receiving and transformation of information from different parts of the body (Farabee 2010). The brain is always in constant communication with the muscles for proper regulation and response in the body. The peripheral nervous system also plays a significant role in the system. The system helps in the integration of the CNS with other parts of the body (Farabee 2010). The basic constituent of the system is the nerves that arise from amalgamation of the axon and dendrites by a white myelin sheath (Farabee 2010). One of such nerves is the cranial nerves. The nerve helps in the collection of an impulse to and from the brain (Farabee 2010). Further, the peripheral nervous system is then divided into sensory (afferent) and motor neurons (efferent). The two neurons are differentiated based on the direction they carry impulse in relation to the central nervous system. For example, the sensory neuron carries an impulse towards the CNS while the motor neuron carries impulse away from the CNS to muscles and glands (Farabee 2010). The motor neuron is also divided into two components. The component includes the somatic nervous system (SNS) and autonomic nervous system (ANS). The somatic nervous system comprises of nerves regulating muscles and external sensory receptors in the body (Farabee 2010). On the other hand, the autonomic nervous system comprises of motor neurons responsible for regulation of internal organs (Farabee 2010).
TAQ 2
There are three different types of neurons. They include sensory, relay, and motor neurons.
Motor neuron


Source: (Biologymad 2004).
The motor neuron plays a significant role in the Central Nervous system. The neuron carries the message from the CNS to the effector (Biologymad 2004). The effector may be a muscle or gland in the body. The neuron is usually characterised by short dendrites and long axon.
Sensory neuron


Source: (Biologymad 2004).
The sensory neuron is also known as afferent neuron. The neuron helps in relaying messages from the receptor to the brain or spinal cord (Biologymad 2004). As a result, impulse moves away from the central organ or point. The neuron is characterised by long dendrites and short axon.
Relay neuron (Interneuron)


Source: (Biologymad 2004).
The interneuron or relay neuron plays a significant role in linking other neurons. As a result, it acts as a bridge between sensory neurons and motor neuron in carrying information (Biologymad 2004). The neuron makes up the brain and spinal cord. The neuron is characterised by short dendrites and short or long axon.
TAQ 3
The unique nature of changing potential is characteristic of a neuron. In a normal circumstance (no stimulation), the membrane of a neuron maintain a negative charge as compared to its surrounding. The neuron at this state of rest is said to be polarized. Moreover, the difference at rest is known as resting potential. The potential arises as a result of ion concentration within the cell. The ions include potassium (k+), sodium(Na+), chloride(Cl-), and carboxylate (RSC n.d.). Inside the cell, the concentration of potassium and carboxylate ions is higher. On the other hand, the concentration remains high in the outer part of the cell for sodium and chloride ions (RSC n.d.). At rest, the membrane allows free flow of potassium ions as compared to other ions. Consequently, as the ions diffuse out of the cell makes inside slightly negative due to the presence of fewer ions. As a result, a balance is achieved between ions entering and leaving the cell leading to resting potential (RSC n.d.). As a result, the membrane is said to be polarised. However, the stimulation of the neuron alters its potential of its membrane. The neuron is said to be depolarised. As a result, there is change in permeability of the membrane and hence easy flow of sodium ions at the site of stimulation (RSC n.d.). The resulting effect is a sudden influx of sodium ions into the axon. As a result, the inside of the cell gets more positive, and hence action potential is achieved (RSC n.d.). Once there are enough sodium ions inside, there is decreased permeability of sodium ions, as opposed to potassium ions due to the positive charge. The entry of potassium ions continues until there is reestablishment of resting potential. Once the potential is achieved, the axon and the membrane are said to be re-polarised (RSC n.d. ). Once the concentration is restored in the first part, the polarisation of subsequent membrane is depolarized (RSC n.d.). The process is repeated, and the propagation leading to transfer of nerve impulse along the axon.
The synapse is a site in which an impulse from a neuron is passed to other neuron or tissue (RSC n.d.). A synapse occurs at the end of the axon and dendrites. The site also plays a significant role in the transfer of impulse. The synaptic knob occurs at the end of the dendrites. The structure also has synaptic vesicles that contain chemicals necessary for transmission of the impulse at the site (RSC n.d.). The main chemical at this site is known as acetylcholine a neurotransmitter. Moreover, there is a pre-synaptic membrane that provides site for binding with adjacent neuron.
On the other hand, the receiving neuron has receptor molecules located on postsynaptic membrane. The gap between the receiving and conducting neuron is known as synaptic cleft. The transmission of impulse occurs through exchange of ions in the membrane leading to propagation of action potentials (RSC n.d.). The ions that play this role are calcium and sodium ions. The two ions interact with acetylcholine in the process. Once a nerve impulse reaches the pre-synaptic membrane it, leads to depolarisation in the membrane (RSC n.d.). As a result, there is change of electrical potential in the region. The effect is increased permeability in favour of calcium ions. The increased inflow of calcium ions prompt synaptic vesicles to join with the inner surface of the membrane (RSC n.d.). Consequently, acetylcholine is released in the gap. On the other hand, the empty vesicles moved back to the cytoplasm. The acetylcholine diffuses across the gap causing fusion with receptor molecule on the receiving neuron (RSC n.d.). The attachment leads to depolarisation of the membrane and hence permeability allows inflow of sodium ions into post-synaptic neuron. Once the acetylcholine is done with its function, it is broken down with the help of water. Receptor molecules release the products and moves back to conducting neurone for reformation of acetylcholine.
Diagram showing the components of a synapse


Source: (RSC n.d.).
TAQ 4
Diagram showing components of a Reflex Arc


Source: (Anonymous n.d. )
The transfer of impulse is a significant process in human. The reflex arc refers to the path followed by an impulse (Anonymous n.d.). There are five components of the process. They include receptor, sensory (afferent) neuron, integration centre, motor (efferent) neuron, and an effector (Anonymous n.d.). For a reflex to occur, there must be two basic components. The components include the sensory and motor neuron. The role of the sensory neuron is to detect stimuli and send signals to the CNS (Anonymous n.d.). A synapse occurs between a sensory and a motor neuron. Moreover, a motor neuron carries the message from the central nervous system to the effector (Anonymous n.d.). The effector acts as a site that receives a response while the receptor receives the stimuli. Moreover, the integration process takes place in the interneuron. The arc helps in movements of various parts of the body such as the limbs, and eyes.
TAQ 5
Name of endocrine
glandLocationHormones
releasedFunction(s) of
Hormones releasedPituitaryBase of the Brain-Follicle-stimulating hormone (FSH)
-Leutinizing hormone(LH)The hormones released in the gland are out of command by the hypothalamus. The hormones released control vital endocrine functions. The FSH leads to development and maturation of follicle in the woman ovaries (Carter 2014). On the other hand, the LH enhances the collapse of the follicle and development of the corpus luteum (Carter 2014)ThyroidIn front of the neck-Thyroxine hormones
-TriiodothyronineThe hormone plays a significant role in body metabolism they regulate metabolism and hence body temperature and weight (Carter 2014). ParathyroidsPosterior to thyroidParathyroid hormoneThe hormone is responsible for regulating the amount of calcium in the blood (Carter 2014).ThymusUpper Chest regionThymosinThe hormone helps the body in resisting some of the infections(Carter 2014).AdrenalOn top of kidney- Epinephrine
- corticosteroidsEpinephrine helps the body to respond to stressors (Carter 2014). The stressor may be fright, anger, caffeine, or reduced amount of sugar in the body. On the other hand, corticostero...