Anatomy and Physiology

Part 1 Topics

The Cell Types of Tissue Organ Systems Disease Causes Disease Pathophysiology

The Normal Cell The cell is the

fundamentalunit of thehuman body.

Cells containall the

necessarycomponents

for life functions.

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

Contains genetic material, DNA, and enzymes necessary for replication of DNA.

Mitochondria

The “Powerhouses” of the cell

Lysosomes

Contain digestive enzymes which protect against disease and produce nutrients

Perioxisomes

Absorb and neutralize toxins

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.

Muscle Tissue Has the capability of contraction

when stimulated. Cardiac tissue is found only within the heart.

Has the unique capability of spontaneous contraction without external stimulation.

Smooth muscle is found within the intestines 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.

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:

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 throughout the body.

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 The natural tendancy of the body to

maintain a steady and normal internal environment

Metabolism Building up (anabolism) and breaking

down (catabolism) of nutrients to create energy

Integumentary System Epidermis

Dermis Subcutaneous Hair Nails

Hematopoietic System Blood

Bone Marrow Liver Spleen Kidneys

Blood Components

The percentage of the blood occupied by the red blood cells

is termed the hematocrit.

White blood Cells

Granulocytes Basophils Eosinophils Neutrophils

Monocytes Lymphocytes

Cardiovascular System Pump

Pipes Fluid

Blood Flow Through the Heart

Blood Flow Through the Heart

Digestive System

Skeletal System

Endocrine System

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.

Endocrine System

The body’s cells interact and intercommunicate

with substances secreted by various body glands.

Signaling Endocrine signaling—hormones

distributed throughout the body. 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.

Nervous System

Pathophysiology

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

From the root “patho” meaning disease.

How Cells Respond to Change and

Injury

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 (1 of 2)

Atrophy—decreased size resulting from a decreased workload.

Hypertrophy—an increase in cell size resulting from an

increased workload.

Types of Cellular Adaptations (2 of 2)

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

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 (1 of 3)

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.

Cell Death (2 of 3)

Necrosis A pathological process Cells swell and rupture Coagulative Liquefactive Caseous Fatty

Cell Death (3 of 3)

Gangrenous necrosis Cell death over a wide area Dry Wet Gas

The Cellular Environment:

Fluid and Electrolytes

Water is the most abundant substance in the human body.

Where the Water is Found

Intracellular fluid—fluid inside the cells.

Extracellular fluid—all the fluid outside the body cells.

Intravascular fluid—fluid within the circulatory system.

Interstitial fluid—fluid outside of the cell membranes but not within the circulatory system.

Percentage of total body weight due to water

distributed into various fluid compartments.

Dehydration

Abnormal decrease in total bodywater. Gastrointestinal losses Increased insensible loss Increased sweating Internal losses Plasma losses

Overhydration

Retention of abnormally high amount of body fluid.

Major sign is edema. In severe cases, heart failure

may occur.

Electrolytes

Electrolytes

Substances that separate in water into electrically charged particles called ions.

Cations have a positive charge.

Anions have a negative charge.

Cations

Sodium (Na+)

Most prevalent cation in extracellular fluid.

“Water follows sodium.” Important in transmission of

nervous impulses. Hypernatremia is an abnormal

increase in sodium. Hyponatremia is an abnormal

decrease in sodium.

Potassium (K+)

Most prevalent cation in the intracellular fluid.

Important in transmission of electrical impulses.

Hyperkalemia is an abnormally high potassium level.

Hypokalemia is an abnormally low potassium level.

Calcium (Ca++)

Plays a major role in muscle contraction as well as nervous impulse transmission.

Hypercalcemia is an abnormally increased calcium level.

Hypocalcemia is an abnormally low calcium level.

Magnesium (Mg++)

Necessary for several biochemical processes.

Closely associated with phosphate. Hypermagnesemia is an

abnormally increased level of magnesium.

Hypomagnesemia is an abnormally decreased level of magnesium.

Anions

Chloride (Cl-)

Negative charge balances the positive charge of cations.

Major role in fluid balance and renal function.

Associated with sodium.

Bicarbonate (HCO3

-) Principle buffer of the body. Neutralizes the hydrogen ion

and other organic acids.

Phosphate (HPO4-)

Important in body energy stores.

Closely associated with magnesium in renal function.

Acts as a buffer, primarily in theintracellular space.

Osmosis and Diffusion

Diffusion is the movement of a substance

from an area of greater concentration to an

area of lesser concentration.

Types of Solutions Isotonic—solutions on opposite

sides of a membrane are equal in concentration.

Hypertonic—the concentration of a given solute is greater on one side of a membrane than the other.

Hypotonic—the concentration of a given solute is less on one side

of a membrane than the other.

OSMOSIS VS.

SOLUTES (1 of 2) Osmosis is the movement of water

from an area of higher WATER concentration to an area of lesser WATER concentration.

Because water is a solvent, it moves from an area of lower SOLUTE concentration to an area of higher SOLUTE concentration.

OSMOSIS VS.

SOLUTES(2 of 2)

Active Transport

The movement of a substance across the cell membrane against the osmotic gradient (toward the side that already has more of the substance).

Faster than diffusion. Requires energy.

Facilitated Diffusion

Certain molecules can move across the cell membrane with the

assistance of “helper proteins.”

Glucose is one example. Depending on the substance, this

movement may or may not require energy.

Osmotic pressure—pressure exerted by the concentration of solutes on one side of a

semipermeable membrane. Oncotic force (colloid osmotic

pressure)—osmotic pressure exerted by large protein

particles.

OSMOTIC VS. ONCOTIC

Starling’s HypothesisNet Filtration =

(Forces favoring filtration) MINUS (–)

(Forces opposing filtration)

Edema

Accumulation of water in the interstitial space due to disruption in the forces and mechanisms that normally

keep net filtration at zero.

Mechanisms that Cause Edema

A decrease in plasma oncotic force.

An increase in hydrostatic pressure.

Increased capillary permeability.

Lymphatic channel obstruction.

Edema (1 of 2)

Can be local or within a certain organ system.

For example:

Sprained ankle vs. pulmonary edema.

Edema (2 of 2)

Water in interstitial spaces is not available for metabolic processes.

Edema, therefore, can cause a relative condition of dehydration.

Acid-Base Balance

Acid-Base Balance

Acid-base balance is a dynamic relationship that reflects the

relative concentration of hydrogen ions in the body.

Hydrogen ions are acidic and the concentration of those in the

body must be maintained within fairly strict limits.

Acidosis — pH below 7.35

Alkalosis — pH above 7.45

A variation of only 0.4 of a pH

unit in either direction of normal can be fatal in humans.

Acid-base relations relevant to pH

Regulation of Acid-Base Balance

Mechanisms to Remove Hydrogen

Ions From the Body

Buffer System (Bicarbonate Buffer

System) The fastest mechanism. Two components of this system

are bicarbonate ion (HCO3-) and

carbonic acid (H2CO3) and are normally in equilibrium with hydrogen (H+).

H+ + HCO3- H2CO3

Hydrogen may combine with bicarbonate to produce

carbonic acid. In other circumstances

carbonic acid will dissociate into bicarbonate and

hydrogen.

Respiratory and Kidney Mechanisms

Increased respirations cause increased elimination of CO2 which causes a decrease in hydrogen ions and an increase in pH.

The kidneys regulate the pH by altering the concentration of bicarbonate ions in the blood.

The Respiratory Component of Acid-Base Balance

Acid-Base Derangements

Caused by abnormal retention of CO2 from impaired ventilation due to problems occurring in the lungs or respiratory center of the brain.

Respiration = CO2 + H2O H2CO3 H+ + HCO3-

Respiratory Acidosis

Caused by increased respiration and excessive elimination of CO2. The CO2 level is decreased and the pH is increased.

Respiration = CO2 + H2O H2CO3 H+ + HCO3-

Respiratory Alkalosis

Results from the production of metabolic acids such as lactic acid. These acids consume bicarbonate ions.

Can be the result of dehydration, diabetes, or medication usage.

H+ + HCO3- H2CO3 H2O + CO2

Metabolic Acidosis

Compensation for metabolic acidosis begins with an

increase in respirations.

H+ + HCO3- H2CO3 H2O + CO2

Metabolic Alkalosis

The pH is increased and the CO2

level is normal. It is usually caused by administration of diuretics, loss of chloride ions associated with prolonged vomiting, and overzealous administration of sodium bicarbonate.

Arterial Blood Gases

pH 7.35 – 7.45

pCO2 35 – 45 mmHg

pO2 80 – 100 mmHg

HCO3-22 – 27 mEq/L

Part 1 Summary

The cell Types of tissue Disease causes Disease pathophysiology