EMT Chapter 7 (Pathophysiology)

Cell metabolism

the sum of the chemical reactions that occur within cells, enabling them to maintain a living state

Hypoxia

lack of adequate oxygen (most common cause of cellular injury)

Areas most impacted by hypoxia

brain, heart, and kidney

Most common type of hypoxia

Ischemia (reduced blood supply)

Infarct

death of tissue due to ischemia

Myocardial infarction

heart muscle dying (heart attack)

Cerebrovascular accident (CVA)

infarct in the brain (stroke)

Hypercarbia

An increase in carbon dioxide

Wheezing suggests

lower airways are partially blocked with fluid or mucus

Perfusion depends on

cardiac output (CO), peripheral vascular resistance (PVR), and the transport of oxygen

Cardiac output

the amount of blood the heart pumps each minute

Cardiac output is determined by

multiplying stroke volume (SV) by heart rate (HR)

Stroke volume

the amount of blood ejected by the ventricles of the heart with each contraction

Venous return

The amount of blood returning to the ventricles

3 tissue layers of vein/artery walls

The innermost layer (tunica intima), tunica media (thickest), and tunica externa or tunica adventitia

Medium-sized arteries

brachial and femoral arteries (distributing)

Large arteries

Aorta, carotid arteries, and pulmonary arteries

Arteriovenous shunts

Some arterioles connect directly to venules, and this enables blood to bypass the capillary network

Functional units of the circulatory system

Capillaries

What areas contain no capillaries?

Cartilage, cornea, and lens of the eye

A precapillary sphincter

Band of smooth muscle that controls the amount of blood entering a capillary network

Large veins (capacitance vessels)

superior and inferior vena cavae

Peripheral vascular resistance (PVR) or systemic vascular resistance (SVR)

is the opposition the blood encounters in the blood vessels as it travels away from the heart

Narrowing of a vessel (vasoconstriction) increases

peripheral resistance

Widening of a vessel (vasodilation)

decreases peripheral resistance

blood pressure formula

= cardiac output × peripheral vascular resistance

Shock is also called

hypoperfusion

Hypovolemic shock

loss of blood, plasma, or water from the body. May be due to: bleeding, vomiting, diarrhea, or burns

Cardiogenic shock

The heart fails to function effectively as a pump

Obstructive shock

when blood flow is slowed or stopped by a mechanical or physical obstruction. May happen when: blood collects in the sac surrounding the heart, or air in the chest due to a lung injury

Distributive shock

Due to massive dilation of the blood vessels. May be due to: massive infection (septic shock) or a severe allergic reaction (anaphylaxis)

Pathogenesis

the mechanism by which a disease develops

Etiology

means the study of cause

A sign (objective findings)

a medical or trauma condition of the patient that can be seen, heard, smelled, measured, or felt by the examiner

A symptom (subjective)

a condition described by the patient

A syndrome

a group of signs and symptoms that together are characteristic of a specific disease or disorder

An antigen

any substance that is foreign to an individual and causes antibody production