Lecture 3 - au.edu.syau.edu.sy/images/courses/medicine/1-1-2/1-2-5.pdf · The facial nerve is an...

English for Medical Purposes 2 – Hisham Badr

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Lecture 3

The Nervous System

Organization of the Nervous System

Nerves

The Nervous system 1

The Nervous system 2

The Eye


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The Organization of the Nervous System

The nervous system is the main communication and decision-making system of the body. The brain, spinal cord, nerves, and sensory organs are all part of the nervous system.

The nervous system is divided into two major areas, the central nervous system (CNS) and the peripheral nervous system (PNS).

The CNS and the PNS

The central nervous system (CNS)

Contains the brain and the spinal cord. The brain and the spinal cord are the control centers of the body. The brain is in charge when you make decisions like where to go on vacation or what to eat for dinner. The spinal cord is in charge of most reflex decisions. Recall that a reflex is an automatic movement. For example if your hand touches a hot stove, you automatically pull away from it.

The peripheral nervous system (PNS)

Contains the nerves that carry messages to and from the CNS. The PNS also contains sensory receptors. Sensory receptors are cells or part of cells that feel things such as pain, heat, and pressure. For example, your fingers contain many sensory receptors. The PNS also contains sensory organs such as the ears, eyes, and nose. Your sensory receptors and sensory organs gather information and then send it along nerves to your brain and spinal cord.

The CNS and the PNS: A Story

The CNS and the PNS have different jobs to do. The following story will show these differences.

One day, a man named Joe was cooking when his hand accidently touched the stove. “Ouch” he yelled. The sensory receptors (ends of the nerves) in Joe’s finger felt pain and heat. These sensory receptors sent a message along a nerve to Joe’s spinal cord. The spinal cord interpreted the message to mean: “Joe’s hand felt pain and heat”. The spinal cord then made a decision for Joe to move his hand away from the stove. The spinal cord sent that message along a long a nerve to the muscles in Joe’s hand and arm, making those muscles contract. Joe had already moved his hand before realizing he was getting burned. This is an example of spinal cord decision. The experience made Joe think about what happened. “that was dumb. I’ll be more careful next time”. The decision of being more careful was made by the brain. Usually automatic movement come from the spinal cord, while ideas are produced by the brain.

Remember, the spinal cord is often in charge of making reflex decisions, obviously Joe


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didn’t have to think about removing his hand from the stove. Let’s look at the steps of Joe’s reflex.

1. Sensory receptors in his hand felt heat and pain. (PNS) 2. A message was sent along nerves (PNS) to the spinal cord (CNS). 3. The spinal cord (CNS) interpreted the message about the heat and pain in his

hand and decided what to do. 4. After the spinal cord decided what to do, it sent a message along a nerve (PNS)

to his hand and arm. 5. Muscles in his hand and arm contracted to move away from the stove.

The brain differs from the spinal cord in function. The brain is in charge of remembering information. A message about pain and heat went to Joe’s brain, the message went to at least two places in his brain, the memory center (to remember not to touch the hot stove again) and the speech center (to direct him to say “Ouch!”).

Cell of the Nervous System:

The major cell of the nervous system is the neuron. There are many different kinds of neurons. Motor neurons send messages from the CNS to move muscles. Sensory neurons send messages to the CNS about what you see, smell, touch, taste, or hear. Most neurons have three parts.

1. The cell body is the widest part of the neuron. It contains most of cell parts needed for the neuron to do its job. It is the decision making part of the neuron.

2. The dendrites are short branches at one end of the cell body. Dendrites receive


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messages from other neurons and send these messages to cell body.

3. The axon is a single long extension at the other end of the cell body. An axon can be as long as your arm or your leg! At the end of an axon, there are branches. These axon branches send messages from the axon to other neurons or to muscle.

Comprehension Check

Circle the correct word(s) to complete each sentence.

1. Motor neurons send messages from CNS to ………………………………….

( a. see – b. move muscles – c. smell – d. hear )

2. Neurons are …………………………….

( a. molecules – b. organs – c. cells – d. tissues )

3. The …………………… of a neuron receives messages from other neurons.

( a. axon – b. cell body – c. dendrite – d. nucleus )

4. You find neurons in the ……………………

( a. brain – b. spinal cord – c. PNS – d. a, b, and c )

5. There is usually only one ……………………….. in the neuron, and it has branches at

the end.

( a. axon – b. cell body – c. dendrite – nucleus )


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Nerves

Neurons are organized into larger structures called nerves. Neurons are cells; nerves are organs. Nerves are organized in a similar way to muscles. Recall that muscles are comprised of fascicles that are, in turn, comprised of bundles of muscle fibers. Nerves are also comprised of fascicles. The fascicles in nerves are comprised of dendrites and/or axon.

Nerves are found in the peripheral nervous system (PNS). They form the connection

between sensory receptors (for example, in the finger tip), the central nervous system

(CNS), and organs. There are two major categories of nerves in the PNS: cranial nerves

and spinal nerves.

Cranial Nerves travel between the brain and other areas in the head. Even

though these nerves are found in the head, they are still part of the PNS. All nerves are

part of the PNS. There are twelve pairs of cranial nerves. These can be classified into

three different types of nerves: sensory, motor, and mixed.

1. Sensory nerves travel from a sensory receptor to the brain. For example, the

optic nerve sends messages from the eye to the brain when you are reading.

Sensory nerves carry “one-way” messages only. Another term for a sensory

nerve is an afferent nerve. It is important to remember that afferent nerves

approach the CNS.

2. Motor nerves travel from the brain to a muscle or gland in the head. Messages

are also “one-way” but travel in the opposite direction of sensory nerves. For

example, the oculomotor nerve sends messages from the brain to the muscles of

the eye. It contains motor neurons and is important in controlling eye movement

(directing the eye to look at something). Another term for a motor nerve is an

efferent nerve. It is important to remember that efferent nerves exit the CNS.

3. Mixed nerves carry messages in both directions. This means that some of the

neurons in the nerve carry messages from the brain to the muscles (efferent

motor neurons), while other neurons in the same nerve carry messages from

sensory receptors to the brain (afferent sensory neurons). The facial nerve is an

example of this type of nerve. The facial nerve sends messages about what

you taste to the brain. The facial nerve also carries messages from the brain to

the skeletal muscles of the face telling you to smile (when you like the food). The

facial nerve has both afferent and efferent neurons, so it’s mixed nerve.


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Spinal Nerves travel between the spinal cord and the rest of the body. There are 31 pairs of spinal nerves that attach to the spinal cord. Spinal nerves are always mixed nerves. Recall that mixed nerves send messages both to and from the CNS. A particular spinal nerve carries messages from a specific area of the body to the spinal cord. It also carries messages from the spinal cord to the muscles in that area of the body. For example, branches of three spinal nerves join together to form the femoral nerve. When you touch the front of your thigh, this nerve has different neurons sending messages to the brain. The femoral nerve also has different neurons that send messages from the brain to the quadriceps muscles so that you can walk.

Comprehension Check

1. Circle the correct word(s) to complete each sentence.

1) There are 31 / 12 pairs of cranial nerves.

2) All cranial nerves connect the brain with places in the head / body trunk.

3) Another term for a sensory nerve is efferent / afferent.

4) All sensory nerves carry messages to / from the brain.

5) Motor nerves send messages to / from the brain.

6) Another term for a motor nerve is afferent / efferent.

7) Both motor nerves and sensory nerves carry messages one way / two ways.

8) Mixed nerves carry messages one way / two ways.

9) Efferent nerves approach / exit the CNS.

10) All cranial / spinal nerves are mixed nerves.

11) Spinal nerves carry afferent / efferent / two-way messages.

12) The brain connects directly with cranial / spinal nerves.

2. Match the terms with their definitions by writing the letters in the correct blanks.

1. Afferent nerves a. Travel away from CNS.

2. Cranial nerves b. Are found in the head.

3. Efferent nerves c. Travel both to and from CNS.

4. Mixed nerves d. Connect with the spinal cord.

5. Spinal nerves e. Travel to the CNS.


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The Nervous System 1

A. Sensory Loss

The central nervous system controls the sensory and motor functions of the body. Diseases of this system therefore lead to loss of some of these functions.

Function Loss Other Symptoms

hearing deafness buzzing or ringing in the ear (tinnitus)

sight blindness double vision (diplopia)

blurring (loss of visual acuity – clarity of vision)

sensation numbness tingling or pins and needles

balance unsteadiness dizziness (vertigo)

B. Motor Loss

Weakness - loss of power

Paralysis – complete loss of power

Tremor – involuntary rhythmic movement, especially for the hands.

Abnormal gait – unusual manner of walking.

Hoarseness – a rough, deep voice - as in vocal cord paralysis

Slurred speech – poor articulation, as in cerebellar disease.

C. Loss of Consciousness

Patients may describe sudden loss of consciousness in a number of ways:

I

passed out.

I had a

fit.

had a blackout. seizure.

fainted. convulsion.

Fit, seizure, and convulsion are all used to refer to violent involuntary movements, as in epilepsy.

Doctors may say : when did you lose consciousness?


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Here is a passage from a textbook on the causes of consciousness

The principal differential between an epileptic fit and syncopal attack, or fainting.

Syncope is sudden loss of consciousness due to temporary failure of the cerebral

circulation. Syncope is distinguished from a seizure principally by the circumstances in

which the event occurs. For example, syncope usually occurs whilst standing, under

situation of severe stress, or in association with an arrhythmia. Sometimes a convulsion

and urinary incontinence – loss of control of the bladder- occur even in a syncopal

attack. Thus, neither of these is specific for an epileptic attack. The key is to establish the

presence or absence of prodromal symptoms, or symptoms that occur immediately before the

attack. Syncopal episodes are usually preceded by symptoms of dizziness and light-

headedness. In epilepsy people may get a warning, known as aura, that an attack is

going to happen.

1. Complete the table

adjective Noun

blind

conscious

deaf

dizzy

numb

light-headed

unsteady

2. Make word combination using a

word from each box

double epileptic prodromal syncopal urinary visual

acuity attack incontinence symptom vision fit

3. A doctor is trying to determine the cause of loss of consciousness in a 52-year-old

man. Complete the doctor’s questions.

Did you lose (1) …………………… suddenly or gradually.

Did you get a (2) …………………… of the attack?

What were you doing before you (3) …………….. out?

Were you worried or under any (4) ………………. at the time?

Did you feel (5) ………………… or (6) ………………… ………………….. before the attack?

Did you lose (7) ……………………. Of your bladder?

Did your wife notice any (8) ………………… movements while you were unconscious?


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The Nervous System 2

A. The Motor System

Examination of the motor system should include assessment of the following:

Muscle bulk (amount of muscle tissue).

Wasting (muscle atrophy).

Muscle tone (amount of tension in a muscle when it is relaxed). Tone can be

increased (spasticity), or decreased (flaccidity).

Muscle power (strength).

Coordination (the ability to use several muscles at the same time to perform

complex actions).

Gait (the manner of walking).

Reflexes.

Involuntary movements, for example a tic or a tremor

B. Tendon Reflexes

Examination of the nervous system normally includes testing the tendon reflexes, for

example the knee jerks, with a tendon hammer (also known as a reflex hammer). The

reflexes may be absent (0), diminished (-), normal (+), or brisk (+++). The plantar

reflexes are also checked. The normal plantar response is a down going ↓ movement

(plantar flexion) of the big toe. An up going ↑ toe (extensor or Babinski response) is

abnormal.


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1. Complete the table

Noun Adjective

absence

diminution

flaccid

spastic

wasted

2. A doctor is giving instructions to a patient during examination of the motor system.

Identify what the doctor is assessing in each case.

a) I’d like you to relax. I’m just going to move your arm up and down.

b) Can I see your hands?

c) Now, I’m going to straighten your arm out. Try to stop me.

d) Can you touch my finger with yours and then touch your nose? Good. Now do it

again with your eyes closed.

3. Complete the sentences.

a) A ……………. hand droops limply to form a right angle with the wrist.

b) ………………. Reflexes are reflexes that are stronger than normal.

c) Muscle ………….. means the muscle reduced in bulk.

d) A tic is a form of ……………………… movement.

e) A key is often used to test the ……………………… response.

f) His ……………… was poor: he could not perform rapid alternating movements.

g) A …………………. ………………… is used to test reflexes.

h) When something is …………………, it is less than normal.


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The Eye

A. Parts of the Eye

B. Examination of the Eye

Here is an extract from a textbook description of how to examine the eye.

Look for squint (strabismus), drooping of the upper lid (ptosis) or oscillation of the eyes

(nystagmus). In lid lag, the upper eyelid moves irregularly instead of smoothly when the

patient is asked to look down.

Next, examine the pupils and note whether:

They are equal in size.

They are regular in outline (evenly circular).

They are abnormally dilated (large) or constricted (small).

They react normally to light and accommodation (focus on near objects).

To test the reaction to accommodation, ask the patient to look into the distance. Hold

your finger in front of their nose, and ask the patient to look at it. The eyes should come

together, or converge, and the pupils should constrict as the patient looks at the finger.

Cataract (opacity of the lens).


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1. Complete the table.

Verb Noun Adjective

accommodate

constriction

convergence

dilation, dilatation

Droop

oscillate

React

2. Match the pictures (1-6) with the conditions (a-f).


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Lecture 4

The Integumentary System

Integument

The Skin 1

The Skin 2


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Integument

Integument is the word used within the medical profession for skin. The integument is the outer covering of the body. It holds all of the parts of the body inside and prevents unwanted things from getting into the body from the outside. The integument has three layers, or regions: epidermis, dermis, and hypodermis (subcutaneous layer). The integument also contain accessory structures such as blood vessels, nerves, nails, hair, oil glands, and sweat glands.

The skin is the largest body organ. The average adult has about 21.5 square feet of skin. The four major functions of the skin are:

1. It protects the body from fluid loss and injury and from the intrusion of harmful microorganisms and ultraviolet (UV) rays of the sun.

2. It helps to maintain the proper internal temperature of the body. 3. It serves as a site for excretion of waste materials through perspiration. 4. It is an important sensory organ.

The skin varies in thickness, depending on what part of the body it covers and what its function is in covering that part. For example, the skin on the upper back is ten times thicker than the skin on the eyelid. The eyelid skin must be light, flexible, and moveable, so it is thin. The skin on the upper back must cover and move with large muscle groups and bones, so it is thick to provide the necessary strength and protection.

The Regions of the Integument:

The skin or integument has three major regions. The epidermis is the outer region of the integument. The dermis is the second region of the integument that lies beneath the epidermis. The hypodermis is located below the dermis region of skin.

The Epidermis

The epidermis is the outer region of the integument, it is comprised of many layers of flattened cells that form a tissue called epithelial tissue. Two important molecules are found in the epithelial tissue: Keratin and Melanin.

Keratin is a molecule found in the top layers of the epidermis. The upper layers of the epidermis are comprised of dead cells that contain keratin. Keratin makes your skin tough and waterproof.

Melanin molecules are also located in the epidermis. Melanin is found in both living and dead cells in the epidermis. The function of melanin is to give color to the person’s skin and to protect the skin from the sun. People with darker skin have more melanin in their skin than people with lighter skin. How much melanin a person has in her skin depends on genetics. People whose ancestors came from hot climates near the equator have


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more melanin than people whose ancestors came from the far north or far south. Sunlight contains ultraviolet (UV) rays that can cause skin cancer.

Comprehension Check

Match the terms with their definitions.

1. Epidermis a. When something bad enters your body. 2. Epithelial b. The harmful rays from the sun which cause skin cancer. 3. Invade c. To send outside of a cell. 4. Keratin d. The top layer of the skin. 5. Melanin e. Helpful bacteria that kill the bad bacteria. 6. Mole f. Small dark area on the skin where melanin is concentrated. 7. Resident bacteria g. A molecule that keeps your skin tough and waterproof. 8. Secrete h. Gives color to a person’s skin. 9. Tumor i. The tissue that comprises the epidermis. 10. UV rays j. A group of cells that multiply in an uncontrolled way. ---------------------------------------------------------------------------------------------------------------------

The Dermis:

The dermis is the second region of the integument. It lies beneath the epidermis and is thicker than the epidermis. The dermis contains mostly connective tissue. The function of this connective tissue is to hold the epidermis to the tissues below it such as muscle and fat. In effect, the dermis holds the epidermis in place so that it doesn’t fall off the body.

The connective tissue within the dermis contains cells and three kinds of protein fibers. However, each type of fiber has a unique purpose. They are:

Collagen fibers : give the skin strength, make it flexible, and hold water to moisturize the skin.

Elastin fibers : allow the skin to stretch.

Reticular fibers : act like a net to hold connective tissue together.

The hypodermis:

the hypodermis is located below the dermis region of skin. The hypodermis is comprised of fat. This fat is called adipose tissue, the function of adipose tissue is to provide protection for the organs and to insulate the body from cold. Adipose tissue varies in thickness among people. Some people whose ancestors came from colder regions have more fat than people whose ancestors came from tropical regions. This is because people in colder regions need more body fat to stay warm.


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Accessory Structures in the Integument:

The integument has several important accessory structures within its layers. The word accessory means extra or in addition. Accessory structures are the extra things inside the skin. They can also be located in one or more regions of the skin. Accessory structures include: blood vessels, nerves, nails, hair, oil glands, and sweat glands.

Blood vessels and nerves: Blood vessels bring nutrients (food and oxygen) to the cells of the integument. They also get rid of waste products. Blood vessels are located in the hypodermis and dermis regions, but not the epidermis. Nerves allow us to have feeling in our skin.

Sebaceous (oil) Glands and Sweat Glands: Sometimes, when you look at yourself in the mirror, you’ll see that your skin or hair looks oily. This oil comes from oil glands, also known as sebaceous glands. These glands are usually found close to hair follicles. Sebaceous glands secrete an oily substance which is called sebum. Sebum has three purposes:

A. To soften the skin. B. To prevent too much water from leaving the skin. C. To kill bacteria.

Nails and hair: Nails are extensions of the epidermis found on the fingers and toes. Nails feel harder than skin because they contain large amounts of keratin called hard keratin.


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Comprehension Check Match the terms with their definitions.

1. Blood vessels a. Oxygen and food are examples of these. 2. Nerves b. These feel such things as heat and pressure. 3. Nutrients c. These carry blood. 4. Sensory receptors d. These carry electrical messages to and from the

brain.

Skin Types

1) Normal – average amount of oil, no acne, no wrinkles.

2) Oily – abundance secretion of oil, pores are large, prone to acne, very little wrinkles.

3) Dry – average to below average amount of oil irritated by hot, dry climate.

4) Combination – normal with oily areas ((forehead, nose, chin)) ( T-zone ), fine wrinkles.

5) Sensitive – allergic reactions to food, cosmetics and drugs.


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The Skin 1

A. Some Types of Skin Lesion

medical term common word Features

macule spot not raised above the surface of the skin

papule spot raised above the surface of the skin

Nodule lump a large papule

Vesicle small blister filled with fluid

Bulla blister a large vesicle

pustule - filled with pus

crust scab dried blood etc. on the surface of the skin

Scales scales a thin layer of epidermis separated from the skin.

cicatrix (cicatrices) scar a mark on the skin after healing

naevus birthmark a colored skin lesion present at birth.

fleshy naevus mole a raised brown naevus.

Verruca wart a nodule produced by HPV.

furuncle boil a large pustule, or skin abscess.

Note: the liquid (often yellow) formed as a result of infection is pus. If a lesion is pustular, it is filled with pus.

B. Rashes A single skin lesion can be regular or irregular in shape. When there are many (multiple) lesions, especially macules or papules, the result is a rash, (or spots in common language); for example the rash of an infectious disease such as rubella. A rash is said to erupt, or break out.

My little boy has broken out in spots in a rash

all over his body

The following features of a skin lesion are usually noted:

(location – size – shape – color – type)

For a rash, note also:

Distribution (widespread – on many parts of the body, or localized – on one part only).

Grouping (scattered – more or less evenly spread out, or in clusters – small groups).


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The Skin 2

A. Injuries to the Skin

Mechanical injuries to the skin are divided into those caused by a blunt force, such as a

punch from a fist, and those caused by a sharp force, such as a knife.

1. Injuries from blunt forces

An abrasion (also called a graze or a scratch) is a superficial (surface) injury

involving only the epidermis, which has been removed by friction.

A scratch is linear, as in fingernail scratches, whereas a graze involves a wider

area, as in abrasions caused by dragging part of the body over a rough surface.

A contusion (also called bruise) is an injury that occurs when blood vessels in the

skin are damaged.

A laceration (also called tear) is a wound involving both dermis and epidermis. It

is usually distinguished from penetrating or incised wounds by its irregular edges

and relative lack of bleeding.

2. Injuries from sharp forces

An incised wound (also called a cut) is a break in the skin where the length of the

wound on the surface is greater than the depth of the wound – for example, a

wound caused by a razor blade.

The depth of a penetrating wound is greater than the superficial length of the

wound – for example a stab wound caused by a knife.

B. Sores

The word sore is a popular term for many different types of skin lesions. A pressure sore

is a skin ulcer caused by pressure, for example the pressure of lying in bed for long

periods (also known as a bedsore, or decubitus ulcer). A cold sore is a lesion caused by

herpes simplex virus (HSV).

1. Complete the sentences.

1. Frequent changes of position are necessary in the immobile patient to prevent

the development of a pressure ……………….

2. He had several ………………….. wounds in the abdomen from the knife.

3. He was knocked unconscious by a heavy …………… to the head.

4. The wounds were only …………….. and required no treatment.


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2. Write the corresponding medical terms for the ordinary English words and say what

kind of force is involved.

Common word Medical term Type of force

Bruise

Cut

graze

Scratch

stab wound

Tear

3. Complete the description of herpes zoster (shingles) by replacing the medical words

in brackets with ordinary English words.

(1)…………………… (herpes zoster) usually starts with pain and soreness. Then red

(2)…………….. (macules) appear that develop into groups of (3)……………….. …………………..

(vesicles) over a particular area on one side of the body. In most patients, new

(4)………………… (lesions) continue to appear for 3 to 5 days. The (5)………………

……………….. (vesicle) become (6) …………………… …………………… …………………. (pustular)

and then form (7)……………………… (crusts). In severe cases, there may be (8)…………………

(cicatrices) afterwards.

Lecture 3 - au.edu.syau.edu.sy/images/courses/medicine/1-1-2/1-2-5.pdf · The facial nerve is an...

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