general principles of pathophysiologyfd.valenciacollege.edu/file/rholborn1/cellular...

GENERAL PRINCIPLES

OF

PATHOPHYSIOLOGY

“Cellular Physiology”

Ray Taylor

Valencia Community College

Department of Emergency Medical Services

Topics

Introduction

The Cell

Types of Tissue

Disease Causes

Disease Pathophysiology

The Cell and the Cellular

Environment

Introduction

Correlation of pathophysiology with

disease process

Cells appear similar to multicellular “social”

organism

Cells communicate electrochemically

When interrupted disease processes can

initiate and advance

Introduction

Knowledge of coordination of specific bodily functions

leads to better understanding of the disease process

Endocrine

Exocrine

Other coordinating receptors

Chemoreceptors

Baroreceptors

Adrenergic

Others: Neurotransmission

Introduction

Understanding disease process is important for

paramedics to better anticipate, correct, and

provide appropriate care

Once knowledge of physical laws and principles

have been gained paramedics can apply these to

the mechanisms and complications of disease

Cells of the immune system and inflammatory

responses are found with every type of trauma or

disease process

The Normal Cell

The cell is the

fundamental

unit of the

human body.

Cells contain

all the

necessary

components

for life

functions.

Cell Structure

Small self sustaining city

Normal balanced environment

Three main elements Cell membrane

Cytoplasm

Organelles

Cell

Major classes of cells

Living cells are divided

into two major divisions

Prokaryotes

Cells of lower plants

and animals

Eukaryotes

Cells of higher

plants and animals

Composed chiefly of

water

Cell

Chief cellular functions Cells become specialized

through processes of differentiation or maturation

Eventually perform one function or act in concert with other cells to perform a more complex task

Conversion of nutrients into

Energy

Waste

Heat

Cell Structure

The cell membrane is

the outer covering that

encircles and protects

the cell.

Cytoplasm is the thick,

viscous fluid that fills and

gives shape to the cell.

Organelles are structures

that perform specific

functions

within a cell.

Organelles

Nucleus

Endoplasmic reticulum

Golgi apparatus

Mitochondria

Lysosomes

Peroxisomes

Nucleus

Largest organelle known

as control center of cell

Contains genetic material

which governs all

activities of cell including

cellular reproduction

Composed of DNA and

proteins

Endoplasmic Reticulum

Network of small channels that has both rough and smooth portions Rough endoplasmic

reticulum functions in synthesis of proteins

Smooth endoplasmic reticulum funcitons in the synthesis of lipids

Golgi Apparatus

Synthesis and

packaging of

secretions such as

mucus and enzymes

Layers of

membranes

Mitochondria

Energy factories of the cell

Powerhouse of the cell

Responsible for provision of cellular energy

Converts nutrients into energy sources

In the form of adenosine triphosphate (ATP)

Lysosomes and Perozisomes

Lysosomes Contain digestive

enzymes

Protect against disease

Production of nutrients

Breaking down bacteria and organic debris entering cell and releasing unstable substances

Perozisomes Absorb and neutralize

toxins

Cilia and Flagella

Cilia

Short hair like projections

from cell

Create fluid movement

around cell

Flagella

Long whip like

projections from cell

Moves cell through

extracellular fluid

Cell Function

All human cells have the same

general structure and genetic

material.

Differentiation causes cells to

become specialized.

There are seven major

functions of cells.

Major Functions of Cells

Movement

Conductivity

Metabolic

absorption

Secretion

Excretion

Respiration

Reproduction

Tissues

Tissue refers to a group of cells that

perform a similar function.

Tissue Types

Epithelial Tissue

Lines internal and external body surfaces and protects the body.

Some forms perform specialized functions: Secretion

Absorption

Diffusion

Filtration

Skin, mucous membranes, lining of intestinal tract.

Skeletal muscle, also called

voluntary muscle, is found

throughout the body.

Cardiac muscle is limited to

the heart.

Smooth muscle, occasionally

called involuntary muscle, is

found within the intestines

and surrounding blood

vessels.

The Three Types of Muscle:

Muscle Tissue

Has the capability of contraction

when stimulated.

Cardiac tissue is found only within the heart.

Has the unique capability of spontaneous stimulation without

external stimulation.

Smooth muscle is found within the intestines,

bronchial tubes and encircling blood vessels.

Generally under control of the autonomic nervous system.

Skeletal muscle allows movement and is

generally under voluntary control.

Most abundant type.

Connective Tissue

Most abundant tissue in

the body.

Provides support,

connection, and

insulation.

Examples include bone,

cartilage, and fat.

Blood is classified as

connective tissue.

Nerve Tissue

Specialized tissue

that transmits

electrical impulses


Examples include

the brain, spinal

cord, and peripheral

nerves.

Organs, Organ Systems, and

the Organism

An organ is a group of tissues

functioning together.

A group of organs working

together is an organ system.

The sum of all cells, tissues,

organs, and organ systems

makes up an organism.

Organ Systems

Cardiovascular

Respiratory

Gastrointestinal

Genitourinary

Reproductive

Nervous

Endocrine

Lymphatic

Muscular

Skeletal

System

Integration

Homeostasis

Homeostasis is the term for the body’s

natural tendency to keep the internal

environment and metabolism steady

and normal.

A significant amount of energy is required to maintain the anatomy and physiology of

the body.

Metabolism

Metabolism is the term used

to refer to the building up (anabolism) and

breaking down (catabolism) of biochemical

substances to produce energy.

The body’s cells interact

and intercommunicate with

substances secreted by various

body glands.

Endocrine Glands

Sometimes called ductless glands.

Secrete hormones directly into the circulatory system.

Some endocrine glands include: pituitary, thyroid, parathyroid, adrenal glands, Islets of Langerhans in the pancreas, testes, and ovaries.

Exocrine Glands

Secrete

substances such

as sweat, saliva,

tears, mucus,

and digestive

juices onto the

epithelial surfaces

via ducts

Signaling

Endocrine signaling—hormones distributed


Paracrine signaling—secretion of chemical mediators

by certain cells that act only upon nearby cells.

Autocrine signaling—cells secrete substances that act

upon themselves.

Synaptic signaling—cells secrete neurotransmitters

that transmit signals across synapses.

Hormones and neurotransmitters are

received by various receptors:

Nerve endings

Sensory organs

Proteins that interact with, and then

respond to the chemical signals and

other stimuli

Many medications act upon

these receptors…

Chemoreceptors respond to

chemical stimuli.

Baroreceptors respond to

pressure changes.

Alpha and beta receptors

respond to neurotransmitters

and medications.

When normal intercellular

communication and normal

metabolism are disturbed, the body

will respond in various ways to

compensate and attempt to restore

normal metabolism,

a.k.a. — homeostasis.

Stressors on a body system are inputs.

The portion of the system creating the input is an effector.

A negative feedback loop exists when body mechanisms work to reverse an input.

Decompensation occurs when the system cannot compensate and restore homeostasis.

Negative Feedback Loop

Body mechanisms that function to reverse or

compensate for a pathophysiological process (or to

reverse any physiological process, whether

pathological or nonpathological

Output of a system corrects the situation that created

the input

Feedback negates the input caused by the original

stressor

Feedback must be orchestrated and synchronized to

maintain homeostasis

Pathology and Pathophysiology

Pathology

Study of diseases and its cause

Pathophysiology

The study of how diseases alter the normal physiological processes of the human body

Disease may include illness or injury

From the root “patho” meaning disease.

How Cells Respond to

Change and Injury

Cellular and Tissue Alteration

Body tends to maintain a constantly

balanced environment and to adapt

(correct or compensate) for any change

that disturbs the balance

Cellular adaptation

Cells adapt to their environment to avoid and

protect themselves from injury

Adapted cells are neither normal or injured (they

are somewhere between these two states)

Cellular Adaptation

Cells, tissues, organs, and organ systems can adapt to both normal and injurious conditions.

Adaptation to external stressors results in alteration of structure and function.

Examples:

Growth of the uterus during pregnancy, dilation of the left ventricle after an MI.

Types of Cellular Adaptations

Atrophy—decreased

size resulting from a

decreased

workload.

Hypertrophy—an

increase in cell size

resulting from an

increased workload.

Types of Cellular Adaptations

Hyperplasia—An increase in the number of

cells resulting from an increased workload.

Metaplasia—Replacement of one type of

cell by another type of cell that is not

normal for that tissue.

Dysplasia—A change in cell size, shape, or

appearance caused by an external

stressor.

Cellular Injury

Hypoxic

Chemical

Infectious

Immunologic/ Inflammatory

Physical agents

Nutritional balances

Genetic factors

Cellular Injury

Hypoxic injury Most common cause of

cellular injury

May result from:

Decreased amounts of oxygen in the air

Loss of hemoglobin or hemoglobin function

Decreased number of red blood cells

Disease of respiratory or cardiovascular system

Loss of cytochromes Iron containing protein in

the mitochondra (electron transport system)

Cellular Injury

Chemical agents causing cellular injury

Poisons

Lead

Carbon monoxide

Ethanol

Pharmacological

Cellular Injury

Infectious injury

Disease causing agents (Pathogens)

Virulence or pathogenicity of microorganisms depends on their ability to survive and reproduce in the human body, where they injure cells and tissues

Disease producing potential depends upon its ability to

Invade and destroy cells

Produce toxins

Produce hypersensitivity reactions

Infectious Injury

Possible outcomes

Pathogen wins

Pathogen and body battle to a draw

Body defeats pathogen

Bacteria

Survival and growth depend upon the effectiveness of

the body’s defense mechanisms and the bacteria’s

ability to resist the mechanisms

Coating protects the bacterium from ingestion and

destruction by phagocytes and capsules may also

function as exotoxins (outside poisonous substance)

Not all virulent extracellular pathogens are

encapsulated mycobacterium tuberculosis can

survive and be transported by phagocytes

Bacteria

Bacteria also produce substances such as enzymes or toxins which can injure or destroy cells

Toxins are produced by many microorganisms

Exotoxins (staph, strep, psuedomonas)

Endotoxins (lipopolysaccharide that is part of the cell wall of gram-negative bacteria)

Fever is caused by the release of endogenous pyrogens from macrophages or circulating WBC’s

Inflammation is one of the body’s responses

Hypersensitivity reactions is an important pathogenic mechanism

Bacteremia or septicemia is proliferation of microorganisms in the blood

Viruses

Viral diseases are among the most common afflictions seen in

humans

Intracellular parasites take over the control of metabolic

machinery of host cells for use to replicate the virus

Protein coat (capsid) encapsulating most viruses allows them to

resist phagocytosis

Viral replication occurs within host cell

Having no organelles, viruses are incapable of metabolism

Viruses do not produce exotoxins or endotoxins

Viruses can evoke a strong immune response but can rapidly

produce irreversible and lethal injury in highly susceptible cells

(as in AIDS)

Immunologic and Inflammatory Injury

Cellular membranes are injured by direct contact with

cellular and chemical components of the immune or

inflammatory process as in phagocytes and others

such as histamine, antibodies, lymphokines

Membrane alterations are associated with rapid

leakage of potassium out of the cell and an influx of

water

Can result in

Hypersensitivity: exaggerated immune response

Anaphylactic: life threatening

Injurious Physical Agents

Cellular damage can be caused by physical agents

Physical agents causing injury

Temperature extremes

Burns

Atmospheric pressure changes (blast injury, deep sea diving accident)

Ionizing radiation

Illumination (eye strain from lighting)

Skin cancer

Noise

Mechanical stressors (trauma)

Injurious Nutritional Imbalances

Improper nutrition contributes to one of the most widely publicized forms of cellular injury

Examples

Atherosclerosis

Vitamin deficiency

Malnutrition

Starvation

Injurious Genetic Factors

Some cellular dysfunctions are caused by genetic

predispostion, either defective genes or altered

chromosomes that a person is born with

Genetic injuries involve

Alterations to the nucleus or cell membrane

Alterations to the shape of cell or receptors of cell

membrane

Alteration to transport mechanism that carries

substances across cell membrane

Manifestation of

Cellular Injury

When cells are injured metabolism is

changed, causing substances to

infiltrate or accumulate to an abnormal

degree in cells.

Cellular Swelling

Results from a permeable or

damaged cellular membrane.

Caused by an inability to

maintain stable intra-and

extracellular fluid and

electrolyte levels.

Fatty Change

Lipids invade the area of injury.

Occurs most commonly in vascular organs, most frequently the liver.

Causes a disruption of the cellular membrane and metabolism and interferes with the vital functions of the organ.

Signs and Symptoms of

Cellular Change

Fatigue and malaise

Altered appetite

Fever

Increased heart rate

associated with fever

Pain

Cell Death

Apoptosis

Injured cell releases enzymes that engulf and destroy the cell.

Cells shrink.

Eliminating damaged and dead cells allows tissues to repair and possibly regenerate.

Cellular Necrosis

Cell death; a pathological cell change

Four forms of necrotic cell change

Coagulative

Liquefactive

Caseous

Fatty

Cellular Necrosis

Coagulative necrosis

Generally results from hypoxia and commonly occurs in kidneys, heart, and adrenal glands

Transparent viscous albumin of the cell becomes firm

Liquefactive necrosis

Cells become liquid and contained in walled cysts

Common in ischemic death of neurons and brain cells

Caseous necrosis

Common in TB

Cells become infected and look like fried cheese

Fatty necrosis

Fatty acids combine with calcium, sodium, and magnesium ions

Gangrenous Necrosis

Tissue death over a wide area

Types

Dry gangrene: results from coagulative necrosis

Wet gangrene: results from liquefactive necrosis

Gas gangrene: results from bacterial infection in tissue generating gas bubbles in cells

Dispatch

You, a paramedic, and your EMT partner

are dispatched to an MVC with injuries.

Dispatch reports that another unit is on

scene and has requested a second

ambulance.

© 2007 by Pearson Education, Inc.

Pearson Prentice Hall, Upper Saddle River, NJ

Arrival

After you notify dispatch of your arrival,

the EMT from the other unit tells you that

they “are bringing the patient over to you

now.”

You and your partner pull the stretcher

out of the back of your rig.

The patient is placed on the stretcher.



Initial Impression

Patient presents as

Fully immobilized

Alert and oriented

Complaining of rib pain



Discussion

• What is your initial impression of the

patient’s status?

• What concerns do you have about the

mechanism of injury (MOI)?

• What are your next, most immediate

actions?



Initial Assessment

You ask your partner to begin an initial assessment in the back of the ambulance while you go and look at the car the patient was in.



Initial Assessment

On the way to the vehicle, one of the firefighters tells you that

Your patient was the restrained driver of vehicle T-boned on the driver’s side

Vehicle then hit tree

Patient self-extricated and was ambulatory when fire services arrived Standing takedown was performed onto

backboard

Passenger required extrication and is in critical condition



Discussion

• Is it necessary to inspect the vehicle?

• Why or why not?

• What does the damage to the vehicle tell

you about the

• MOI?

• Potential for injury to your patient?



Initial Assessment

You note

Significant front-end and passenger-side damage

One foot of intrusion into driver’s compartment

Windshield on driver’s side intact

Glass on driver’s door shattered



Initial Assessment

You return to the ambulance where your partner has performed an initial assessment.

He reports

Airway open, patient describes slight difficulty breathing

Bruising to the left lateral rib cage

Possible decreased lung sounds on the injured side

No bleeding noted

No neurological deficits noted



Initial Assessment

Vital signs

HR = 104 regular

RR = 20 regular

BP = 136/80

SaO2 = 96% on room air



Discussion

• What are your immediate concerns?


actions?



Assessment

Oxygen administered via nonrebreather mask

You confirm your partner’s initial assessment findings and perform a chest exam.



Assessment

When asked, the patient states

He did not hit his head or lose

consciousness.

He was able to get out of the car and walk

around without neck or back pain.

His only complaint is left-sided chest pain.

Worse pain with deep inspiration

“I can’t catch my breath.”



Assessment

Your assessment reveals

Bruise to lateral/anterior chest wall Crepitus with palpation

Lung sounds slightly diminished on injured side, clear bilaterally

Head, neck, abdomen, pelvis, and extremities all atraumatic

Skin slightly pale, warm, dry



Discussion

• What injuries might the patient have

suffered?



actions?



Ongoing Assessment

You ask your partner to begin the 15-minute response to the trauma center.

Repeat vital signs

HR = 110 regular

RR = 22 regular

BP = 134/80

SaO2 = 99% on 15 Lpm

Breath sounds still diminished on left



Assessment

You place the patient on the cardiac monitor.

Interpretation?



Treatment/Assessment

As you are preparing for large-bore IV access with a 16-gauge, 1-1/4 inch catheter, the patient says that he is having trouble breathing.

You note

He is becoming restless and diaphoretic

RR = 28 shallow, labored

HR = 128 regular

Skin pale, diaphoretic



Discussion

• What do you think is responsible for these

sudden changes?



actions?



Treatment/Assessment

You immediately prepare a prepackaged needle thorocostomy kit.



Treatment

A 12-gauge thorocostomy needle is affixed to a 10 cc syringe



Ongoing Assessment

You now note

HR = 134 regular

RR = 34 shallow


Very weak radial pulse

Skin pale, cold, diaphoretic

Jugular vein distention (JVD)

Absent lung sounds on left side



Discussion

• Is this patient in shock?

• What classification of shock?

• Compensated or decompensated?

• What is your next, most immediate action?

• Assist BVM ventilations?

• Intubation?

• Needle decompression?



Treatment

You identify the midclavicular line in the second intercostal space.



Treatment

You prepare the area with an iodine swab and insert the catheter.



Treatment

You feel a “pop” as the catheter passes into the pleural space.

The syringe plunger pulls back easily and air is aspirated.

The needle is removed.



Discussion

• What suggests that the needle

decompression was successful?

• What assessment findings will confirm that

the needle decompression was

successful?



Treatment

Heimlich valve attached



Ongoing Assessment

You reassess the patient.



Ongoing Assessment

Reassessment reveals:

Lung sounds increased on left

Color returning to skin

Decreased patient anxiety

SaO2 increasing steadily



Ongoing Assessment

Vital signs

HR = 108 regular

RR = 22 regular

BP = 130/76




Discussion

• Do the assessment findings suggest that

the needle decompression was

successful?


actions?



Treatment

You initiate large-bore IV access.

1000 cc normal saline with large-bore tubing hung, rate KVO

Patient tells you he is feeling better but still feels he cannot catch his breath.



Treatment

You contact medical control and give a report.



Discussion

• Is the fact that the patient is experiencing

shortness of breath a concern?


actions?



Ongoing Assessment

Ongoing assessment reveals

Patient alert and oriented

Lung sounds still slightly diminished on left

No JVD or tracheal deviation

Skin slightly pale, warm, dry

Head, neck, abdomen, pelvis, and extremities still appear atraumatic



Ongoing Assessment

Vital signs

HR = 102 regular

RR = 20 regular

BP = 126/76




Discussion

• How do you explain the patient’s

shortness of breath?


actions?



Treatment

You prepare the patient for arrival and transfer to the ED.

Patient's only complaint at time of arrival is chest pain and shortness of breath.



ED Treatment and Beyond

ABCs assessed

Oxygen administration continued

Central venous access obtained

Imaging studies

Trauma radiograph series obtained

Left-sided pneumothorax and pulmonary contusion identified

No other injuries noted




Laboratory studies

Complete blood count (CBC), type and cross, coagulation profiles

Arterial blood gas (ABG)

Chest tube placed

Patient sent to CT

No additional injuries noted




Admitted to the trauma service for observation

Lung reexpands without complication

Patient discharged 3 days later



Thank you!

general principles of pathophysiologyfd.valenciacollege.edu/file/rholborn1/cellular...

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