-
functions of the cardiosystem
- carry O2 and nutrients
- remove waste (CO2)
- maintain homeostasis (temp, hydration, osmosis)
-
-
-
most common inherited morphology in animals
patent ductus arteriosus
2nd- pulmonic stenosis
-
forces that act on SA node
- spontaneous originating impulses
- vagal nerve
- sympathetic fibers
-
heart block
- any interruption of impulse pathway
- AV Bundle most common
-
P wave represents
atrial depolarization
-
P-R interval represents
filling time for ventricles
-
QRS Complex represents
- atrial repolarization
- ventricular depolarization
-
S-T segment represents
filling time for atrium
-
T wave represents
ventricular repolarization
-
cardiac reserve
diff between the work capability at rest and that during max physical exertion
-
O2 available to tissues is dependent on these 2 things:
- cardiac output
- amount of O2 extracted from blood
-
two systems generate blood pressure:
- general vascular system- LV
- pulmonary vascular system- RV
-
arterial blood pressure is maintained by
- cardiac output
- peripheral vascular resistance
-
if blood pressure on arterial side is low, do this:
- give fluids to increase cardiac output
- epinephrine to cause vasoconstriction and increase BP
-
humoral agents that regulate arterial pressure and cardiac output
- renin
- atrial natriuretic peptides (ANP)
- NT-ProBNP (predictor of heart failure)
-
paracrine agents that regulate arterial pressure
- nitric oxide
- endothelin- peptide secreted by endothelial cells, constricts vascular smooth muscle of arterioles
-
venous side contains what percentage of the total blood vol
70-80%
-
types of capillaries
- arterio-venous "thorough-fare" capillaries- blood flow is continuous, controlled by sphincters in arterioles and along the capillary wall
- secondary capillaries "true" capillaries- no muscle, passive diffusion
-
venous return controlled by
- inspiration
- venous contraction
- valves
other factors: heart beat, muscular activity, peristalsis of intestinal tract, and gravity
-
nerve fibers that secrete acetylcholine are said to be
cholinergic
-
nerve fibers that secrete nor-epinephrine are said to be
adrenergic
-
explains that some postganglionic fibers of the sympathetic system are cholinergic (release acetylcholine)
Grey Rami
-
piloerector muscles
make the hair stand up on the back of the cat
-
parasympathetic
cholinergic
- neurotransmitter: acetylcholine
- receptors: nicotinic, muscarinic
-
-
acetylcholine activates two diff types of receptors
-
poison from toadstools
- muscarine
- activates only muscarinic receptors
-
activates only nicotinic receptors
nicotine
-
-
2 adrenergic receptors
- epinpehrine excites alpha&beta
- nor-epi excites alpha
-
catecholamines
- epinephrine
- nor-epi
- l-dopa
- dopamine
- dopaminergic
- *all originate from adrenal medulla of adrenal gland
-
alpha receptors sensitive to
epinephrine and nor-epi
-
beta receptors sensitive to
epinephrine only
-
alpha 1 receptors
- vasoconstriction
- blood is shunted from non-essential survival areas to the heart and skeletal muscles
-
alpha 2 receptors
associated with analgesia and sedation
-
beta 1 receptors
- located in myocardium
- increase rate and strength of contraction of depolarization wave in heart muscle
-
beta 2 receptors
bronchodilation
-
what is shock?
reduced cardiac output and vasodilation
-
what determines the level of BP in the vascular system?
cardiac output and peripheral vascular resistance
-
what happens when we give 1:10,000 epinephrine for shock?
- compensatory shock reaction:
- alpha 1- vessels in periphery constrict to raise BP and divert blood flow to vital organs
- beta 1- increase in strength and contraction rate of myocardium
- beta 2- bronchodilation for breathing and vascular dilation in the heart to allow for easy blood flow
-
anaphylactic reaction process
- injection of foreign protein (ex. penicillin)
- histamine release (mast cells/basophils)
- vasodilation of capillaries
- increase capillary permeability
- blood plasma moves into tissues
- decrease blood vol
- reduced blood flow >hypoxia >death
-
degrees of shock
- compensatory phase
- progressive phase
- irreversible phase
-
compensatory phase
- all arterioles except coronary and cerebral vessels constrict to maintain arterial pressure
- elevation of pulse and increase in cardiac output
-
progressive phase
- heart cannot pump sufficiently due to fatigue
- decrease cardiac output and O2 to alveoli&respiratory center causing vasodilation
- body is wanting to vasodilate to reduce friction so blood will flow more easily
-
irreversible shock
no treatment effective as heart is irreparable
-
TX of shock
- fluids- to increase blood vol and replace some of the blood plasma pressure lost to tissues
- corticosteroids- restore capillary strength and reduce vasodilation
- warm body
-
dog comes in w/ shock, what do you do step-by-step?
- 1. place indwelling catheter
- 2. start on LRS @ shock drip
- 3. solu-delta-cortef (if does not work then..)
- 4. 1:10,000 epinephrine
|
|