Special pathology - cardiology Flashcards
veterinary cardiology focuses on?
small animal medicine
it just isn’t as applicable to large animal medicine.
The heart is
a muscular four-chambered pump that simultaneously supplies blood to the pulmonary and systemic circulatory beds.
Vascular system is subdivided: (4)
arterial
capillary
venous
lymphatic segments
Heart lies within a fibroelastic sac =
pericardium
wall of the heart is composed of three layers:
epicardium
myocardium
endocardium
heart contains in order of blood flow four major blood vessels:
vena cava,
pulmonary artery
pulmonary vein
aorta
name the heart Valves:
tricuspid / right atrioventricular
pulmonic semilunar
mitral / bicuspid / left atrioventricular
aortic semilunar
Stroke volume or systolic volume (SV) is defined as
The amount of blood ejected per beat by the left ventricle into the aorta
(or from the right ventricle into the pulmonary artery).
Cattle 0.5 – 0.6 l (at rest)
Horse 0.8 – 0.9 l
Cardiac output (CO) is defined as
cardiac minute volume so the total volume of blood pumped by the heart per minute (denoted with symbol ‘Q’).
Cattle 30 – 35 l
Horse 20 – 30 l
Cardiac output can be increased by how much
5 – 6 times.
The maximum and minimum stroke volumes characterise accommodation dynamics, or the extent of adaptation.
In the case of short-term physical loads, what type of regulation of cardiac function occurs?
neural regulation (via the parasympathetic and
sympathetic nervous systems), and endocrine regulation
Reflex regulation of cardiac function occurs via
the cardiovascular centre of medulla oblongata (myelencephalon).
Mechanical pumping of the heart must be preceded by
an electrophysiologic process that triggers a coordinated
chronologic sequence of electrical events that result in muscle contractions.
This electrophysiologic process is made possible by a network of special conducting fibers that are collectively referred to as the cardiac conduction system.
the two phases of a cardiac contraction are
-sequential contraction (systole)
-relaxation (diastole)
Nerve supply to the heart: (3-4)
is autonomic and includes
-sympathetic-
-parasympathetic &
-nonadrenergic noncholinergic innervation
What provides the force of cardiac contraction?
What controls the flow and volume of the heart?
Cardiac myocytes provide the force of contraction;
the conduction system and the nervous system control the flow and volume.
Angiocardiography
method of following the passage of blood through the heart and great vessels by means of the intravenous injection of a radiopaque fluid, whose passage is followed by serialized X-ray pictures.
purpose of Cardiac catheterization
may be performed to diagnose or evaluate: Causes of congestive heart failure or cardiomyopathy.
used to examine your heart valves or take samples of blood or heart muscle.
may also be done to treat some types of heart conditions
Cardiac myocardial damage can be detected by increased activity of serum enzymes and isoenzymes such as: (5)
creatine kinase (CK)
lactate dehydrogenase (LDH)
troponin T (TnT)
troponin I (TnI)
aspartate aminotransferase (AST)
increased plasma concentrations of what may indicate
cardiac disease
besides serum enzymes, the 2 hormones:
plasma natriuretic peptides (A type [atrial] ANP and B type [brain BNP)
These hormones are synthesized and released by cardiac muscle cells in increased amounts during cardiac dysfunction.
Heart failure is
a progressive clinical syndrome in which impaired pumping decreases ventricular ejection and impedes venous return.
In heart failure, the heart fails either by
decreased blood pumping into the aorta and/or pulmonary artery to maintain arterial pressure (low-output heart failure)
or by an inability to adequately empty the venous reservoirs (congestive heart failure).
low-output heart failure broadly involves
decreased blood pumping into the aorta and/or pulmonary artery to maintain arterial pressure
congestive heart failure broadly involves
an inability to adequately empty the venous reservoirs