Bio 201 Lab 9 Essay Example

is to release chemicals that stimulate other cells and generate and transmit action potentials. Conversely, a nerve consists of a group of axons. Neurons are the fundamental cells in the nervous system and consist of the cell body, dendrites, and an axon. A multipolar neuron derives its name from the numerous fibers that extend from the cell body. Dendrites convey electrical signals towards the cell body while axons transport electrical signals away from it.

Activity 3: The Neuroglia and Supporting Cells Activity 4: Structure of a Nerve Questions:
A. Describe the functions of the following parts of a nerve:
- Endoneurium: It is the connective tissue that encloses the myelin sheath of a nerve fiber within fascicullus.
- Epineurium: This is the most outer layer that surrounds the peripheral nerve.
- Perineurium: It is the protective sheath that surrounds bundled fascicles.
- Fascicle: It refers to a bundle of nerve fibers enclosed by perineurium.
B. What is a nerve? A nerve is a bundle of peripheral axons carrying sensory information to CNS and motor information from CNS.
C.

The connective tissue wrappings are essential for establishing a connection between the spinal cord and peripheral nerves, providing structure to the nerves. Additionally, they play a crucial role in distinguishing between the central nervous system (CNS) and the peripheral nervous system (PNS). The PNS encompasses all neural structures except for the brain and spinal cord, including sensory receptors, peripheral nerves, and motor endings that connect to and from the external environment. In this system, myelination and regeneration are handled by Schwann cells. Conversely, in the CNS which comprises of the brain and spinal cord, oligodendrocytes carry out myelination since regeneration is not possible.

This paragraph discusses the

structure and function of nervous tissue in both the central nervous system (CNS) and peripheral nervous system (PNS). GABA is the primary inhibitory neurotransmitter in the CNS, while glycine serves this role in the PNS. Nervous tissue consists of two main cell types: neurons, which transmit electrical signals, and supporting cells that surround and envelop neurons. These cells have armlike extensions originating from the soma in the CNS and nerves in the PNS. Dendrites are short branches that serve as input regions for neurons, while axons are slender processes with a uniform diameter that originate from the hillock.

Typically, each neuron has only one non-branched axon. Step 2: Clarify the concepts related to nervous tissue by selecting Loyola University/ Part 6: Nervous Tissue. Locate a slide that includes each of the following terms. Describe the term in your own words and indicate the slide number. 1. Axon is a single fiber that carries information from the soma to the synaptic sites of other neurons. 2. Dendrite functions as the receiving region of the neuron and conducts electrical impulses towards the cell body. 3. Axon Hillock, located on the side of the soma and has a conical shape, is where the axon originates. 4.

The soma, also known as the control center of the neuron, contains Nissl bodies, which are made up of rough ER and are found in the nucleus of the soma. Axodendritic synapses connect axons to dendrites. The myelin sheath, a whitish fatty segmented covering, surrounds most long axons, protecting them and providing electrical insulation between fibers while increasing the speed of nerve impulse transmission. Muscle spindles are sensory receptors in muscles

that detect changes in muscle length and communicate them to the central nervous system. Pacinian corpuscles are connective tissue wrapped around nerve endings located in deep skin layers. Astrocytes, the most abundant and highly branched glial cells, provide support and bracing for neurons, anchor neurons to their nutrient supplies, guide the migration of young neurons, and control the chemical environment. Microglial cells are small ovoid cells with spiny processes that act as phagocytes to monitor neuron health. Nodes of Ranvier are gaps in the myelin sheath between adjacent Schwann cells and serve as sites for axon collateral emergence. This information relates to Lab Exercise 11/Activity 1 and 2 in the Gross Anatomy of the Central Nervous System Lab Report.

Assignment-1: The following text provides a detailed description of the location, structure, and body activities controlled by each section of the brain mentioned below.

1. The medulla oblongata is located at the lowest part of the brain stem and forms a part of the ventral wall of the 4th ventricle along with the pons. In this area, there is a choroid plexus present in the 4th ventricle. The pyramids are two ridges formed by coricospinal tracts, and their crossover points are where decussation of these tracts occur.

The medulla is responsible for controlling autonomic functions such as breathing, digestion, heart and blood vessel function, swallowing, and sneezing. It also serves as a pathway for motor and sensory neurons from the midbrain and forebrain.
The pons is located between the midbrain and the medulla oblongata. It is a bulging region of the brainstem that forms part of the front wall of the fourth ventricle. The pons contains fibers that connect

higher brain centers and the spinal cord, facilitating transmission of impulses between the motor cortex and cerebellum. Additionally, it plays a role in cranial nerves III, VI, and VII while housing nuclei related to reticular formation.

The pons is responsible for various functions including arousal, autonomic control, relaying sensory information between the cerebrum and cerebellum, and sleep. The midbrain, located between the diencephalon and the pons, contains important structures such as the Cerebral crus (which contains descending pyramidal motor tracts) and the cerebral aqueduct (connecting the 3rd and 4th ventricles). It also controls visual and auditory systems along with eye movement. Positioned dorsal to the pons and medulla is the cerebellum.

The reticular formation, which makes up 11% of the brain's mass and is located under the occipital lobes of the cerebrum, has three main columns - raphe nuclei, medial cell group, and lateral cell group - running along the length of the brain stem. It forms connections with various parts of the brain such as the hypothalamus, thalamus, cerebellum, and spinal cord. Its primary function is to ensure precise timing and appropriate patterns for skeletal muscle contraction. In addition to regulating levels of consciousness and attention (arousal), it also plays a role in controlling levels of arousal and attention (consciousness). On the other hand, there are paired ovid shaped masses that shape the superolateral walls of the third ventricle known as thalamus structures.The thalamus and hypothalamus are vital components of the brain. The thalamus contains four groups of nuclei (anterior, ventral, dorsal, and posterior) that are connected at the midline by the intermediate mass. It is responsible for sensory perception and regulation of motor functions as

it projects and receives fibers from the cerebral cortex.

Located beneath the thalamus, the hypothalamus covers the brainstem and forms the inferolateral walls of the third vesicle. It plays a crucial role in maintaining homeostasis by connecting with structures in both the endocrine and nervous systems. Additionally, it serves as a control center for numerous autonomic functions of the peripheral nervous system (PNS).

The pituitary gland, also known as the hypophysis, releases eight major hormones and is involved in various functions such as temperature regulation, control of food and water intake, sexual behavior and reproduction, control of daily cycles in physiological state and behavior, and mediation of emotional responses. The pineal gland is located in the epithalamus and secretes melatonin which regulates sleep and mood. This gland is situated at the most dorsal portion of the diencephalon and forms the roof of the third ventricle. Cerebrospinal fluid is secreted by the choroid plexus in the brain. The superficial gray matter consists of two parts: the cerebrum and cerebral cortex which together make up 40% of its mass. They are responsible for voluntary movements, understanding, communication, thought processes, perception and memory as well as social abilities including language use and problem solving. It's important to note that all areas within this cortex must work together for each functional behavior; individual functional areas cannot act alone. The limbic system structures can be found on both cerebral hemispheres' medial aspects (inner sides) as well as within certain parts of the diencephalon like hypothalamus and anterior nucleus of thalamus. Within this system exist various structures with different functions.The rhinencephalon, responsible for olfactory senses, and the amygdala, associated with emotions, are both

involved in various functions previously mentioned. The hypothalamus also plays a role in these functions. Additionally, the anterior nucleus of thalamus has an unknown function. Moreover, the cingulate gyrus is a significant structure that expresses emotions through gestures.

Assignment 2:
1. Label the diagrams on Lab Report: Exercise 11: Gross Anatomy of the Central Nervous System -Activity 1. You do not need to submit these diagrams.
2. Answer the questions on Lab Report: Exercise 11: Gross Anatomy of the Central Nervous System- Activity 2.
Purpose: What is the purpose of this exercise? Are there any safety concerns associated with this exercise? If so, list them and the precautions that should be taken.
The purpose of this exercise is to identify and understand the functions of brain structures using diagrams and dissection. Additionally, it involves comparing the sheep brain with the human brain and learning about cranial and spinal nerves.

Safety concerns include the contamination and proper use of instruments during dissection. Activity 1: Structures of the Brain 1. Label the Lateral View of the Brain at right using the table from the Procedures. Central Sulcus, Spinal Cord, Frontal Lobe, Cerebellum, Temporal Lobe, Occipital Lobe, Pons, Parietal Lobe, Medulla Oblongata 2. Label the Mid Sagittal View of the brain below using the table from the Procedures. Spinal cord, Pineal gland, Cerebellum, Thalamus, Medulla oblongata, Hypothalamus, Fourth ventricle, Mammillary body, Pon,s Corpus callosum, Cerebral aqueduct

Using the table from Procedures 3, designate the right Ventral View of the brain. Furthermore, utilize the same table to identify the Brain Association and Cortical Function Areas on the corresponding diagram.

Activity 2: The Sheep Brain Dissection Questions:
A. When comparing the human brain diagram with

that of a sheep, which primary region of the brain (cerebrum, diencephalon, cerebellum, or brain stem) is significantly more prominent in humans? What could potentially explain this substantial disparity? Humans possess a larger cerebrum compared to sheep. This dissimilarity might be attributed to higher cognitive abilities found in humans.

B. The olfactory bulbs in humans and sheep differ significantly in size. Humans rely more on visual cues, resulting in a decreased need for olfactory sensation compared to sheep who heavily rely on their sense of smell.
C. Notably, the cerebellum differs structurally between humans and sheep. While the human cerebellum is divided into two parts, the sheep cerebellum forms one mass. This distinction may be attributed to the higher complexity of the human brain as it requires greater cerebral functioning.
D. The size discrepancy of the brain stems between sheep and humans carries importance; however, additional information or context is necessary for a full understanding of its implications.

The human brain is larger in size because humans have more complex sensory and motor needs. This exercise has contributed to my comprehension of brain anatomy. It has enhanced my understanding by allowing me to utilize diagrams and dissect the brain. Step 5 involves the cranial and spinal nerves, which are connected to Lab Exercise 11-Activity 3 and 4. I recommend performing these activities. However, please note that there is an error in the spelling of the abducens and glossopharyngeal nerves on page 104 of the cranial nerves picture in the manual.

Assignment-1: Answer to the following questions. 1. Which cranial nerve(s) is (are) needed to perform each of the following? (0. 5 points each)
a. crying because you broke a

present
CNVII
b. chewing holiday treat
CNVII, CNIX, CNXII, CNX
c. seeing snowflakes
CNII
d. smiling for a family picture
CNVII
e. bowing your head
CNXI
f. listening to your favorite music
CNVIII
g. singing Christmas carols
CNX
h. raising the eyelids in surprise
CNVII, CNIII, CNIV
i. having a tooth-ache from eating too many cherry chocolates
CNIX
j. focusing the lens of your eye so you can read this assignment
CNII, CNIV

2.

Which spinal nerve might be damaged in each of the following situations? (0.5 points each)

a. unable to extend the leg - femoral nerve

b. unable to flex the leg - Tibial nerve

c. pain in the medial thigh - femoral nerve

d. difficulty opposing thumb and fingers to pick up objects - Ulnar nerve

e. crutch paralysis/arm paralysis while using crutches - radial nerve

f. carpal tunnel syndrome - median nerve

g. tingling that results when you hit your "funny bone" - ulnar nerve

h. paralysis of diaphragm - phrenic nerve

Assignment-2: Answer to the questions for Lab Report: Exercise 11: Gross Anatomy of the Central Nervous System- Activity 3 and 4.

Activity 3: The Cranial Nerves Questions:

A. Fill in the following information about the twelve cranial nerves: ?????????????

B. Which cranial nerves would be involved in the following activities? Smelling a flower: Olfactory nerve Shrugging your shoulders: Accessory nerve Tasting freshly baked cookies: Facial nerve, Glossopharyngeal nerve, Vagus nerve Slowing your heart rate: Vagus nerve

Activity 4: The Spinal Cord and Spinal Nerves Questions:

A. Label the numbered structures below using the diagram from the Procedures or your textbook as reference.

B.

Complete the table by listing the names of the primary spinal nerves that serve specific areas. Provide a

definition for plexus, which is an interconnected network of nerves. Discuss the importance of having two hemispheres in the brain. Reflect on what you have learned from this activity and consider how this knowledge could benefit your career and any other relevant thoughts. Also, share your thoughts on drawing slides. Remember to include all requested items in your lab submission.

Cell Function Location (CNS/PNS)

astrocytes Support and brace neurons to nutrient blood capillaries CNS

Microglia Provide protection and sense neuron injuries. Can be phagocytic. CNS

Ependymal cells Ciliated cells found in the cavities of the brain. Help to circulate cerebrospinal fluid. CNS

Oligodendrocytes Makes the myelin sheath in the central nervous system. CNS

Satellite cells Surround neuron cell bodies with ganglia. Function is mostly unknown. PNS

Schwann cells Produces the myelin sheath in the peripheral nervous system PNS

Cranial Nerve Function Is it Sensory/Motor/Both? I. Olfactory nerve smell sensory II.

Optic nerve: responsible for vision sensory.

Oculomotor nerve: controls eye movements, opening of eyelid, pupillary constriction, and focusing motor.

Trochlear nerve: controls eye movements motor.

Trigeminal nerve: responsible for touch, temperature, and pain on the face both motor- involved in mastication.

Abducent nerve: controls lateral eye movement motor.

Facial nerve: involved in taste, facial expression, secretion of tears saliva and nasal and oral mucus both.

Auditory nerve: responsible for hearing and equilibrium sensory.

Glossopharyngeal nerve: involved in taste, touch, pressure, pain, and temperature sensations from tongue and outer ear- regulates respiration and blood pressure- salivation, swallowing, gagging both.

X. The vagus nerve is responsible for taste, sensation of hunger, fullness, gastrointestinal discomfort, swallowing speech, deceleration of heart, bronchoconstriction, gastrointestinal secretion and motility. XI. The accessory nerve is responsible for swallowing head and neck and shoulder movements. XII. The hypoglossal nerve is responsible

for tongue movements of speech, food manipulation, and swallowing.

The nerves in the cervical plexus serve the head, neck, and shoulders. The phrenic nerve serves the diaphragm. The sciatic nerve serves the posterior thigh. The femoral nerve serves the anterior thigh. The radial nerve serves the arm muscles. The musculocutaneous nerve serves the anterior forearm. The lumbar plexus serves the abdominal wall. The ulnar nerve serves the medial side of the hand. The fibular and tibial nerves serve the leg and foot.

The lab report consists of several steps, including describing three slides (6 points), identifying and defining 12 terms (12 points), answering two questions (no points allotted), describing the structure of the brain (12 points), naming the cranial and spinal nerves (8 points), and reflecting on what was learned during the lab (2 points). In addition, there is a manual lab report for exercises 10 and 11 worth 35 points.

Total Points: 75