principles of pathophysiology

medulla oblongata

maintains homeostasis by managing respirations

tidal volume

volume of air moving in and out during each breath cycle

hypoxia

low oxygen levels

hypercapnia

high carbon dioxide levels

chemoreceptors

detect changing oxygen and carbon dioxide levels

plasma oncotic pressure

proteins in plasma attract water away from area around cells and pull it into bloodstream

hydrostatic pressure

water pushed back out of blood vessels toward cells

excessive permeability

• capillaries leak fluid out of their walls

• caused by sever infection (sepsis), high altitude, and certain diseases

hypertension

• systemic vascular resistance (SVR)

• various conditions lead to abnormal constriction of vessels, leading to an unhealthy, high pressure level

• major risk factor in stroke and heart disease

what is the average stroke volume (output) of blood?

70 mL per contraction

stroke volume is based on:

• preload - amount of blood returning to heart

• contractility - how hard heart squeezes

• afterload - pressure the heart has to pump against to force blood out into the system

what reduces cardiac output?

• slowing heart rate or decreasing stroke volume

• very fast heart rate (there is an inadequate amount of time for heart to refill between contractions)

what do pediatrics compensate for with high heart rates?

• poor perfusion

• lack of contractile muscles

• inability to regulate the force of contraction

mechanical problems for heart dysfunction:

• physical trauma

• squeezing forces

• cell death (heart attack)

electrical problems

• damage to heart’s electrical system

• unorganized rhythms and rate problems

perfusion

regular delivery of oxygen and nutrients to cells and removal of waste products

hypoperfusion

• inadequate perfusion (shock)

• breakdown in cardiopulmonary system - can result in death of patient

four categories of shock:

• hypovolemic - low blood volume

• distributive - low blood vessel tone

• cardiogenic - heart fails to pump

• obstructive - blood cannot flow

signs of compensated shock:

• slight mental status changes

• increased heart rate

• increased respiratory rate

• delayed capillary refill time

• pale, cool, clammy skin

• sweating

decompensated shock

• occurs when compensatory measures fail

• characterized by decreased blood pressure and altered mental status

irreversible shock

• occurs when inadequately perfused organ systems begin to die

• patient death commonly follows

body is 60% water

• intracellular (70%)

• intravascular (5%)

• interstitial (25%)

edema

swelling associated with the movement of water

major organs of the endocrine system:

• brain

• kidneys

• pancreas

• pituitary gland

• thyroid gland

• adrenal glands

causes of endocrine system dysfunction:

• organ or gland problems

• present at birth or result of illness

• too many hormones (Graves’ diseases - too much thyroid hormone, or problems with heart rate and temperature regulation)

• not enough hormones (type 1 diabetes)

• adrenal insufficiency (affect steroid hormones such as cortisol or aldosterone)

• medications that suppress the immune system suppress adrenal function

• can result if patients stop taking prescribed steroids

symptoms of digestive dysfunction:

• gastrointestinal bleeding

• vomiting and diarrhea