Anatomy and Physiology

Essay 1

1. Cranial nerves

Cranial nerve type	Functions	Origin in the CNS	Origin outside the CNS
Olfactory nerve	Smell	Medulla	The abdomen
Abducens nerve	Eye movement	Pons of the brainstem	The eye socket
Vagus nerve	Autonomic, motor, and sensory functions	The olfactory bulb	The bottom of the colon
Optic nerve	Vision	The cortex	The retina

2. spinothalamic, corticospinal, and posterior column-medial lemniscus tract

The spinothalamic tract is a pathway that descends from the spinal cord. Its function is to transmit temperature, pain, as well as crude touch. These are transmitted to the thalamus’ somatosensory region. This pathway runs from the thalamus to the skin. When the pathway is infected, the symptoms are the loss of temperature, pain, proprioception, light touch, as well as vibration (Betts et al., 2018). 

The corticospinal tract (CST) is part of the descending tract of the spinal system that comes from the brainstem or the cortex. The pathway has many functions that include controlling the activity of the motor neuron, afferent inputs, and spinal reflexes. The most critical function of the pathway is mediating the voluntary distal movements. In the case of an infection, the symptoms include weakness, atrophy, spasticity in the flexia, and fasciculation (Betts et al., 2018). 

Essay 2

1. The three differences between the Motor, sensory, and Associated Areas in the brain

The cerebral cortex is divided into three functional areas including the motor, sensory, and associated areas. 

Sensory cortex	Motor cortex	Associated areas
Primary auditory cortex	Primary motor cortex	Posterior association area (auditory, sensory, and somatosensory association areas)
Primary somatosensory cortex	Premotor cortex	Anterior association (prefrontal cortex)
Primary visual cortex	Supplementary motor area (SMA)	Limbic association area

Functions of the associated areas

The association areas of the cortex help in giving sensations we feel some meaning. Each primary area of the cortex has an association area used in the projection of the sensations. Here is where the stored memories are drawn from in order to give meaning to the sensations people feel. For instance, they help in recognition of the sound or an ambulance (Betts et al., 2018). 

The anterior association area comprises of the prefrontal cortex. It is responsible for receiving the information from the posterior association area. This is the process enables the integration of information with past experiences using the limbic association area. On the other hand, the limbic association area is on the frontal lobe’s medial side. The function of the area is helping in the formation of memories. These are then translated to the motor responses as well as processing emotions. This is the part that is used for social interactions and people expressing their personalities (Betts et al., 2018). 

2. Errors in Refraction

Hyperopia: it is a condition that makes it difficult for an individual to see close by objects

Myopia: is the condition making it difficult for a person to see objects that are far away

Presbyopia: a condition that makes it hard for individuals to have an up-close focus

Astigmatism: the condition that makes it impossible for the eye to evenly focus light on the retina

(Betts et al., 2018)

Structures of the inner ear

The cochlea: it helps in the transformation of electrical impulses that go to the brain understandable sound. 

The auditory nerve: it helps in carrying information between the brain and the cochlea.

The vestibular: it registers the movements of the body thereby making sure there is a balance

(Tortora & Derrickson, 2008)

Essay 3

1. Tectospinal tract

The tectospinal tract helps in the conveyance of nerve impulses to the contralateral skeletal muscles from the superior colliculus.a sign of damage could be a patient’s inability to turn his head when a flashlight is directed to his eyes. At the same time, it would be hard for such a patient to follow the doctor’s finger movements. He may also be unable to read words as they move down the screen (Tortora & Derrickson, 2008). 

2. Sensory receptors

The classifications of sensory receptors are: 

1. Chemoreceptors, e.g., peripheral, central chemoreceptors
2. Thermoreceptors, e.g., warm and cold
3. Mechanoreceptors 
4. Photoreceptors 
5. Pain receptors

(Tortora & Derrickson, 2008)

References

Betts, J. G., Kruse, D. H., Young, K. A., Poe, B., DeSaix, P., Korol, O.,  & Womble, M. (2018). Anatomy and physiology.Tortora, G. J., & Derrickson, B. H. (2008). Principles of anatomy and physiology. John Wiley & Sons.