HAP4 Central Nervous System

Nervous System

...our window to our internal and external surroundings

Characteristics of Life

A line is drawn between the living and nonliving by characterizing life. These characteristics include having cells, metabolism, the capacity to reproduce and respond to its surroundings.

Responsiveness

Responsiveness is the ability of an organism to adjust to changes in its internal and external environments. An example of responsiveness to external stimuli could include moving toward sources of food and water and away from perceived dangers. Responsiveness can also be internal, as in the case of maintenance of homeostasis.

Key Function

The nervous system collects information or stimuli around, process that information and then respond to it with the help of the PNS and the CNS.

Multiple Choice

What is "stimuli"?

• A major organ in the brain that is a part of the nervous system.

• What your body does to a change or a signal.

• A change or a signal your body receives.

Multiple Choice

The nervous system lets your body know what is going on around you and______________

• changes what is bad for your body.
• maintains the conditions inside your body such as your temperature. 

Multiple Choice

TRUE or FALSE

Viruses are considered living things.

• True

• False

Multiple Choice

Sensory organs such as eyes and nose are part of the Central Nervous System.

• True

• False

Multiple Choice

Which of the following is not a recipient of 'response' or output from the brain?

• contracting skeletal muscle

• elevated heart beats

• sensitivity of nose to scent

• blinking of the eye

Neuron

The fundamental unit of impulse transmission.

The next few slides present the kinds and parts of a neuron and their corresponding functions. Familiarize yourself with each before you answer the questions.

Cell body

The largest part of a typical neuron is its cell body. The cell body contains the nucleus and much of the cytoplasm. It carries the genetic information, maintains the neuron's structure, and provides energy to drive activities.

Dendrites

Short, branched extensions called dendrites spread out from the cell body. They receive impulses from other neurons and carry impulses to the cell body. 

Axon

The long fiber that carries impulses away from the cell body is the axon. The axon ends in a series of small swellings called axon terminals. A neuron may have dozens of dendrites, but usually only one axon. Axons and dendrites of different neurons form bundles of fibers called nerves. 

Myelin Sheath

The axons of some neurons are insulated by a membrane known as the myelin (my uh lin) sheath. Inside the myelin sheath are the Schwann cells. These cells play crucial roles in the maintenance and regeneration of the motor and sensory neurons of the peripheral nervous system.

Nodes

The myelin sheath around a long axon has many gaps, called nodes (nodes of Ranvier). Impulses move along the axon by jumping from one node to the next. Impulses travel faster along these axons than along axons without myelin. 

Synapse

At the end of the neuron, the impulse reaches an axon terminal. The axon terminal may pass the impulse along to another cell. For example, a motor neuron may pass impulses to a muscle cell. These impulses cause the muscle cell to contract. The point where a neuron transfers an impulse to another cell is called a synapse (sin aps). 

Kinds of Neurons

• Sensory

• Interneuron

• Motor Neuron

Sensory Neurons

Sensory neurons carry impulses from the sense organs to the spinal cord and brain. 

Interneurons

Interneurons do high-level work. They process information from sensory neurons. Then they send commands to other interneurons or to motor neurons. 

Motor Neurons

Motor neurons carry impulses from the brain and the spinal cord to muscles and glands.

Multiple Choice

When comparing sensory and motor neurons, which of these statements about the morphology of sensory neurons is true?

• Sensory neurons have short dendrites and long axons.

• Sensory neurons have long dendrites and short axons.

• Sensory neurons have long dendrites and long axons.

• Sensory neurons have short dendrites and short axons.

Multiple Choice

What is the function of a sensory neuron?

• To communicate pain signals from the skin to the brain

• To pass signals from the central nervous system to the limbs and other body parts in order to initiate movement

• To detect and directly respond to signals from the external environment

• To detect signals from the environment, convert them to impulses, and pass them along to the central nervous system

Multiple Choice

The cell shown is most likely an example of

• Sensory Neuron

• Interneuron

• Motor Neuron

Multiple Choice

Which structure primarily functions to receive impulses?

• B

• C

• E

• G

Multiple Choice

Which of the following maintains the neuron structure and provides energy for impulse transmission?

• A

• C

• E

• F

Multiple Choice

Which of the following helps maintain and regenerate motor and sensory neurons?

• B

• C

• E

• G

Multiple Choice

Which of the following allows nerve impulses to move faster?

• A

• B

• D

• F

Multiple Choice

What is the structure B called?

• Axons

• Dendrites

• Schwann cells

• Synapse

Multiple Choice

What is the structure C called?

• Nodes of Ranvier

• Cell Body

• Schwann cells

• Terminals

Multiple Choice

What is the structure D called?

• Synapse

• Myelin Sheath

• Dendrite

• Axon

Multiple Choice

What is the structure E called?

• Myelin Sheath

• Nodes of Ranvier

• Axon

• Neurotransmitter

Multiple Choice

The image shows a Purkinje cell. Which kind of neuron is it?

• interneuron

• motor neuron

• interneuron

Multiple Choice

Which neuron is most likely located in your spinal cord?

• x

• y

• z

Multiple Choice

Which neuron is most likely connected to your eardrums?

• x

• y

• z

The Central Nervous System

The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord. The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement.

The Brain

The brain is the control point of the central nervous system. The major areas of the brain are the cerebrum, cerebellum, and brain stem. Each of these areas is responsible for processing and relaying information.

Three major parts

• Cerebrum (biggest part)

• Cerebellum (below the cerebrum)

• Brainstem (connects the brain to the spinal cord)

Cerebrum

This is the largest part of the brain. It performs higher functions such as stimuli interpretion, speech, reasoning, emotions, and fine control of movement.

Cortex and Grey Matter

When brain is cut (in coronal or frontal section), it shows the white and grey matter. Grey matter is found on the surface – cortex.

White matter is composed of myelinated neurons (covered with myelin sheath) and situated inside the cortex.

unmyelinated (grey matter) transmit impulses slowly, myelinated (white matter) very quickly

Corpus Callosum

Lengthways, cerebrum can be divided into two hemispheres (left and right) connected by the fibers of the corpus callosum in the middle. This allows the two hemispheres to coordinate and communicate.

The red area is the Corpus Callosum

Each hemisphere is related with a particular task.

Multiple Choice

The central nervous system only includes the brain

• True

• False

Multiple Choice

The main parts of the brain include

• frontal, parietal, temporal, and occipital lobes

• cortex, cerebrum, midbrain

• grey matter, white matter, corpus callosum

• cerebrum, cerebellum, brain stem

Multiple Choice

Which is myelinated?

• white matter

• grey matter

• both

Multiple Choice

Which kind of neuron transmit impulses faster even at long distances.

• myelinated

• unmyelinated

• both impulses transmit at the same rate

Multiple Choice

Which hemisphere is associated with logic and mathematical tasks?

• left

• right

Multiple Choice

Which hemisphere is associated with speech and comprehension?

• left

• right

Multiple Choice

Which hemisphere is associated with...

Drawing a picture of an imaginary castle

• left

• right

Multiple Choice

Which hemisphere is associated with...

Daydreaming when you should be studying!

• left

• right

Multiple Choice

Which hemisphere is associated with...

Talking to your teacher or parents.

• left

• right

Lobes of the Cerebrum

Each of the brain hemispheres can be divided into four lobes: frontal, parietal, temporal, and occipital. Each lobe is associated with specific brain activities and commands.

The next slide shows these associations.

Frontal Lobe

The frontal lobe plays a role in many higher level functions of your brain. This can include:

• voluntary movements,

• speaking and writing

• attention and concentration,

• working memory,

• processing recently acquired information,

Frontal Lobe

• reasoning,

• organization and planning

• problem-solving

• regulation of emotions and mood,

• reading the emotions of others

• personality expression

• motivation,

• evaluating rewards, pleasure, and happiness

• impulse control controlling social behaviors

Parietal Lobe

The parietal lobe contains the sensory and the motor cortex. These are related to

• sensing tough, taste, temperature

• spatial navigation

• controls movement

Temporal Lobe

• Understanding language and Hearing

• Memory

• Sequencing and organization

Occipital Lobe

• Interprets vision (color, movement, and light)

• depth, distance, location

Multiple Choice

Which lobe of the cerebral cortex are associated with

Color and depth interpretation

• frontal lobe

• parietal lobe

• temporal lobe

• occipital lobe

Multiple Choice

Which lobe of the cerebral cortex are associated with

executive functioning and decision making

• frontal lobe

• parietal lobe

• temporal lobe

• occipital lobe

Multiple Choice

Which lobe of the cerebral cortex are associated with

memory and auditory interpretation

• frontal lobe

• parietal lobe

• temporal lobe

• occipital lobe

Multiple Choice

Which lobe of the cerebral cortex are associated with

remembering directions between home and school

• frontal lobe

• parietal lobe

• temporal lobe

• occipital lobe

Multiple Choice

Which lobe of the cerebral cortex are associated with

feeling the summer heat

• frontal lobe

• parietal lobe

• temporal lobe

• occipital lobe

Deep Structures

Deep within the cortex are the white matter and the inner structure of the brain. It includes the thalamus, hypothalamus, pineal gland, and the pituitary gland.

Thalamus

The thalamus is a small structure within the brain located between the cerebral cortex and the midbrain and has extensive nerve connections to both. The primary function of the thalamus is to relay motor and sensory signals to the cerebral cortex.

Hypohalamus

The hypothalamus is a small region of the brain. It is located at the base of the brain, near the pituitary gland. While it's very small, the hypothalamus plays a crucial role in many important functions, including: releasing hormones. regulating body temperature.

Pituitary Gland

The pituitary gland is called the 'master gland' as the hormones it produces control so many different processes in the body. It senses the body's needs and sends signals to different organs and glands throughout the body to regulate their function and maintain an appropriate environment.

Cerebellum

Beneath the cerebrum is the cerebellum. Its function is to coordinate muscle movements, maintain posture, and balance.

Brain Stem

It acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.

It can be divided into the midbrain, the pons, and the medulla oblongata.

Midbrain

The midbrain is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation.

It is also a switchboard allowing the brain to communicate with the rest of the nervous system.

Pons

The pons is the largest part of the brainstem, located above the medulla and below the midbrain. It is a group of nerves that function as a connection between the cerebrum and cerebellum (pons is Latin for bridge).

Medulla oblongata

The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is a cone-shaped mass of neurons responsible for autonomic (involuntary) functions.

Spinal Cord

The spinal cord is a long, fragile tubelike structure that begins at the end of the brain stem and continues down almost to the bottom of the spine. The spinal cord consists of bundles of nerve axons forming pathways that carry incoming and outgoing messages between the brain and the rest of the body.

Spinal Cord

The spinal cord is protected by the vertebrae (spinal column) and by the meninges.

Multiple Choice

Which of the following is NOT located in the brainstem?

• midbrain

• medulla

• thalamus

• pons

Multiple Choice

Which of the following is considered the master gland as it releases hormones that trigger other glands to perform their function.

• brainstem

• pituitary

• medulla oblongata

• hypothalamus

Multiple Choice

Which of the following is responsible for maintaining posture and balance?

• brainstem

• cerebrum

• cerebellum

• spinal cord

Reflex Physiology

Many of our daily activities are made possible by RAPID, PREDICTABLE, and INVOLUNTARY responses to stimuli

These responses always go in the same direction and through the same neural pathways called reflex arcs.

Two types of Reflexes

1. Somatic Reflexes -

stimulates skeletal muscles

2. Autonomic Reflexes -

stimulates smooth muscles, the heart, and glands

Simple Reflex Arc

Simple reflex arcs allow for a rapid and involuntary response without the need for cognition and decision-making.

This may involve two or three neurons but always require at least 5 elements.

5 elements of the reflex arc

• sensory receptor

• sensory neuron

• synapse or interneurons that join sensory and motor neurons

• motor neuron

• effector organ

Multiple Choice

Which of the following is not part of a reflex arc?

• sensory organ

• sensory neuron

• interneuron

• cerebrum

• motor neuron

Multiple Choice

Which of the following does not define reflex?

• quick

• predictable

• involuntary

• decided upon

Multiple Choice

Which portion of a neuron is located near the sensory organs or sensory receptors?

• axon

• myelin sheath

• dendrites

• nodes

Traumatic Brain Injuries, and Diseases

​

Concussion

–Slight or mild brain injury

–Bleeding & tearing of nerve fibers happened

–Recovery likely with some memory loss

Contusion

–A more severe TBI

–Nervous tissue destruction occurs

–Nervous tissue does not regenerate

Cerebral edema

–Swelling from the inflammatory response

–May compress and kill brain tissue

Cerebrovascular Accident

–Commonly called a stroke

–The result of a blocked or ruptured blood vessel supplying a region of the brain

–Brain tissue supplied with oxygen from that blood source dies

–Loss of some functions or death may result

Alzheimer's Disease

•Progressive degenerative brain disease

•Mostly seen in the elderly, but may begin in middle age

•Structural changes in the brain include abnormal protein deposits and twisted fibers within neurons

•Victims experience memory loss, irritability, confusion and ultimately, hallucinations and death

Meningitis

–Inflammation of the meninges

–Can be caused by a viral, bacterial, or microorganism infection

–Causes headaches, neck stiffness, confusion, sensitivity to light and sound

–Can be life-threatening 

Hydrocephalus

(“water on the brain”)

–Accumulation of CSF in the brain

–Exerts pressure on the brain causing brain damage

Multiple Choice

This brain injury / disorder is characterized by bacterial infection to the protective layers of the CNS.

• hydrocephalus

• concussion

• meningitis

• alzheimer's disease

Multiple Choice

This brain injury/disorder is characterized by enlargement of the head due to large amounts of fluids which can put pressure on the brain and cause tissue damage.

• hydrocephalus

• concussion

• meningitis

• alzheimer's disease

Multiple Choice

This brain injury/disorder is characterized by degeneration of the grey matter, leading to memory loss, irritability, and death.

• hydrocephalus

• concussion

• meningitis

• alzheimer's disease

Multiple Choice

Connective tissues which protect the brain and spinal cord are called the __________.

• vertebrae
• cranium
• meninges
• spinal nerves

Multiple Choice

A soccer ball comes flying toward you. You throw up your hands to be avoid being hit in the face. Which is the stimuli?

• The ball coming towards you.
• Throwing up your hands to stop the ball.

Multiple Choice

Name the two major parts of the central nervous system.

• The brain and the skull.

• The brain and the body.

• The spinal cord and the brain.

• The spinal cord and the body.

Multiple Choice

The brain is made up of three major parts. What are they?

• The occipital lobe, the parietal lobe, and the frontal lobe. 
• The spinal cord, the cerebrum, and the cerebellum. 
• The brain stem, the cerebrum, and the cerebellum. 

Multiple Choice

Which is the stimuli and which is the response?
Sweating
Heat from the sun

• Sweating is the stimuli, heat is the response
• Heat is the stimuli, sweating is the response

Multiple Choice

Which part of the brain coordinates the actions of muscles and helps you maintain balance?

• brain stem
• cerebrum
• cerebellum

Multiple Choice

Which part of the brain controls all involuntary actions?

• brain stem
• cerebrum
• cerebellum

Multiple Choice

If you had one word to describe the function of the parietal lobe it would be:

• Movement

• Sensory

• Balance

• Emotions

Multiple Choice

What is the gap between two neurons called?

• Impulse

• Synapse

• CNS

• Inter neuron

Multiple Choice

This part of the neuron receives chemical messages from the neurotransmitters of other neurons. It is labeled A in the diagram.

• Dendrite

• Axon

• Axon Terminal

• Cell Body

Multiple Choice

The part of the neuron that insulates the axon and increases the speed of the neural message within the neuron.

• Synapse
• Dendrite
• Myelin Sheath
• Axon Terminal Button

Multiple Choice

What letter represents the Parietal Lobe?

• A
• B
• C
• E

Multiple Choice

What letter represents the Temporal Lobe?

• B
• C
• D
• F

Multiple Choice

_____ neurons carry messages away from the central nervous system and out to muscles or glands. The RED neuron in diagram.

• sensory

• motor

• inter

• central

Multiple Choice

Which statement best describes a reflex arc?

• Slow response that you have to think about

• Rapid response to protect body from harm

Multiple Choice

Which statement best describes a reflex arc?

• Slow response that you have to think about

• Rapid response to protect body from harm