Download Nrsg 407 Disorders of Blood Vessels

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Transcript
DISORDERS OF BLOOD
VESSELS
Chapter 8
Elements Determining B/P



Heart rate
Stroke volume: blood pumped
by a ventricle in one
contraction
Peripheral resistance:
turbulence-induced friction
which reduces velocity of the
blood
Cardiac Terminology



Vasomotor center: cluster of neurons in the
medulla that regulates BP via arterial smooth
muscle
Baroreceptors: receptors in the aorta and
internal carotid that sense pressure changes
within large vessels
Chemoreceptors: recognize levels of oxygen,
CO2, and pH in blood
Hormones affecting BP



Epinephrine and
norepinephrine – raise BP
Antidiuretic hormone (ADH)
– vasoconstrictor that
raises BP
Renin-angiotensin system
(RAAS) – controls BP and
fluid balance
Control of
Blood
Pressure
Three Types of Lipids



Triglycerides
Phospholipids
Steroids
Triglycerides




Neutral fat
Energy source
Three fatty acids attached to glycerol
Account for 90% of total lipids in body
Phospholipids



Essential to building plasma membranes
Replace one of fatty acids in a triglyceride
Best-known phospholipids are lecithins
Steroids


Common chemical structure is steroid ring
Cholesterol is most widely known of steroids
 Vital
& natural component of plasma membrane
 Necessary for production of bile acids, Vitamin D,
estrogen, cortisol, & testosterone
 Not necessary in the diet—body makes enough
cholesterol
Lipoproteins




Carriers of lipid molecules
Consist of triglycerides, cholesterol &
phospholipids with protein carrier
Protein carrier is known as apoprotein
Three types: low-density lipoproteins (LDL),
high-density lipoproteins (HDL), & very lowdensity lipoproteins (VLDL)
LDL

LDL transports cholesterol from liver to organs
& tissues
 Used
to synthesize other steroids & build plasma
membranes


Carries highest amount of cholesterol
Known as “bad” cholesterol
 Contributes

to CAD & plaque deposits
Broken down for energy or stored for future
use as energy
HDL


Manufactured in small intestine & liver
Reverse cholesterol transport
 Assists
in transport of cholesterol away from body
tissues & back to liver

Known as “good” cholesterol
 Transports
cholesterol for removal & destruction
from the body

Used for energy
VLDL

Primary carrier of triglycerides in blood
TYPES of HTN

Primary (Essential)
(90%)
Risk Factors
 No known cause


Secondary (10%)
Disease process primary
 HTN caused by disease
process

Diagnosis



Dx based on 2 or more
measurements
3 separate visits
SBP >140, DBP >90
Stepped Care Approach to Treating
HTN




Step 1: Lifestyle modifications
Step 2: Drug therapy is added
Step 3: Drug class or dose may be changed or
another drug added
Step 4: Addition of more anti-HTN agents until
blood pressure is controlled
Atherosclerosis


Hardening of the arteries
3 varieties:
 Arteriolosclerosis
 Consequence
 Monckeberg
of HTN
medical sclerosis
 Calcification
of the media in the large arteries of
patients over 50
 Atherosclerosis
 Lifestyle
disease characterized by fatty deposits in the
arterial wall
Atherosclerosis Pathogenesis


Due to a subtle, nonlethal damage to
endothelial cells
Cause: abnormal blood lipid concentration,
especially LDL
 Also
known to injure endothelium:
High blood uric acid
 Blood homocysteine
 IV drug use

Clotting mechanism: Process of
Hemostasis



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Vessel spasms & local
vasoconstriction occurs
Platelets released toward
injury
Stickiness, cling to each
other
Aggregation: thrombin, ADP,
thromboxane A2, and von
Wildebrand’s factor
Coagulation Cascade




Fibrin threads form to create
clot
Plasma proteins converted to
active forms
Intrinsic pathway converts
prothrombin to thrombin
Extrinsic pathway activated
when blood enters tissue
spaces
Hemostasis Terminology






PT – prothrombin time
aPTT – activated partial
thromboplastin time
Bldg time, Plts, LFT’s, ACT
Thombocytopenia –
deficiency of platelets –
suppressed bone marrow
function
Hemophilia
Von Wildebrand’s disease
Hemostasis Terminology


Thrombus – stationary clot
Embolus – traveling clot
Statins





Interfere with cholesterol synthesis
Can produce a 20-40% decrease in LDL
cholesterol levels & increase HDL levels
First drugs of choice to reduce blood-lipid
levels
Avoid macrolide antibiotics &
immunosuppressants during statin therapy
Examples are: Mevacor, Zocar, Lescol, Crestor
Statins

Role of the nurse is:
 Monitor
liver function tests before & during the
first few months of therapy
 Watch for signs of GI upset
 Do not use with breastfeeding or pregnancy
 Watch for drug interactions with Coumadin,
Digoxin, Estrogen & grapefruit juice