Week 7: Vascular Perfusion: Bleeding/Clotting, Anemia Hypertension Flashcards
what is the difference between homeostasis and allostasis?
homeostasis: think BALANCE or stability of the systems that maintain life
pH
con. of different ions in the ECF (Na, Ca)
osmolality of ECF
glucose levels
arterial O2 tension
Allostasis -under stress defence mechanisms
adaptation to changing external and internal environment
arterial BP
HR
body core temp
con of circulating hormones
sleep-wake cycle
energy metabolism
what does hemodynamics consist of?
systemic circulation:
arteries supply tissues with nutrients and O2 rich blood
veins return blood to pulmonary circulation
Left atrium and left ventricle to aorta = back to right atrium and right ventricle
pulmonary circulation:
right atrium and right ventricle pulmonary artery to lungs - pulmonary veins to Left atrium and left ventricle
re O2 and returned to systemic circulation
what is CO = HR x SV?
cardiac output = heart rate times stroke volume
ex. 60 bpm x o.1 L/beat = 6 L/minute
what is cardiac preload?
this is when the volume of blood returned to the heart pre systole - which exerts pressure on the ventricle walls
description: filling force applied to the heart
when the heart stretches it generates more force to effectively pump the increased load - Frank Starling mechanism (has limits)
increased preload - increased O2 demand of the myocardium, but is more O2 efficient than increasing HR
what is cardiac after load?
description: the pressure the ventricle must overcome to eject blood into the arteries
when contraction - LV must generate more pressure than aortic diastolic pressure
pressure must be great enough to overcome peripheral resistance
reduced after load with vasodilators is a useful therapy for failing heart
increased after load can decrease stroke volume
what does perfusion connect to?
pain
cognition
elimination
gas exchange
mobility
nutrition
patient education
inflammation
intracranial regulation
stress and coping
true or false regarding how the body clots:
Perfusion is needed to sustain life, supply oxygen and nutrients to tissues.
When we have an injury, the body must a way stop losing blood while still maintaining perfusion to the tissues. This is a controlled process called hemostasis.
In order to form clots we only need platelets in the blood to work together to form the mature and functional fibrin clot
Platelets (thrombocytes) are blood cells made in the bone marrow and stored in the spleen.
The liver does not make most of the clotting factors.
false; third one - clotting factors as well
last one: the liver does
where does stem cells originate from?
bone marrow
what falls under stem cell?
erythroblast, myeloblast, mono blast, lymphoblast, megakaryoblast
what does megakaryoblast develop into?
megakaryoblast - megakaryocytes - thrombocytes (platelets)
what are the two pathways that fall under clotting cascade?
intrinsic and extrinsic
explain extrinsic pathway?
External cellular injury (trauma, laceration)
Collagen exposed in the vessels activates clotting.
Bacteria or inflammation can also trigger clotting
Generally Protective
explain intrinsic pathway?
No trauma: Internal conditions trigger clotting.
Venous stasis, lack of blood flow, plaques in vessels, too many clotting factors
Less protective, often problematic
what are some labs used to measure blood clotting?
Activated partial thromboplastin time (aPTT)
International normalized ratio (INR)
Prothrombin time (PT)
Platelet count
what is Activated partial thromboplastin time (aPTT)?
purpose:
Assessment of intrinsic coagulation by measuring factors I, II, V, VIII, IX, X, XI, XII
normal values:
25-35 sec
explain International normalized ratio (INR)
purpose:
Standardized way of reporting PT- compares PT with a control value
normal values
0.8-1.2
prothrombin time (PT)
purpose
Assessment of extrinsic coagulation(blood going from solid to semi solid) by measurement of factors I, II, V, VII and X
normal values
11-16 sec
platelet count
purpose
Count of number of circulating platelets
normal values
150X109/L to 400x109/L
what falls under problem clots: Virchow’s Triad
Blood Stasis
Hypercoagulability
Endothelial injury
- risk factors clot formation are associated with these parts of the triad.
true of false: A clot of this type is called a thrombus. A thrombus will trigger inflammation. A piece of the clot that breaks off and travels around the body is called an embolus.
true
true or false: deep vein thrombosis is a problem clots
true
select all that is true about DVT:
Thrombus forms in the deep veins
May be asymptomatic
Common symptoms include:
Calf or groin pain on affected side
Sudden onset unilateral edema Increased warmth
Redness (rubour) to affected limb
all true
how do you diagnosis for DVT?
Physical assessment, confirm with venous duplex ultrasonography
what is superficial vein thrombosis?
Usually superficial leg veins- close to the skin surface
* Tenderness, rubour, warmth, pain, inflammation and induration along the vein
* Vein appears as a palpable cord
* Edema rarely occurs
* If left untreated, DVT can occur