Chapter 11: Brain (Cardiovascular system) Flashcards
What is the Cerebral arterial Circle of Willis
Arterial supply of the Brain
what artery serves the brain stem and cerebellum
Basilar artery
it form the anterior and posterior blood supplies in the circle of willis
Carotid Arteries and Vertebral arteries
pressure wave of blood (expansion and recoil of blood vessels that occurs with each heart beat)
Pulse
known as ___________ because can compress to stop bleeding
where pulse is easily palpated for grade, force, regularity and rate
pressure point
is the force of blood exerts against wall of blood vessels
determined by pumping action of the heart and size/diameter (lumen) of blood vessels
Blood Pressure
pressure at the peak of ventricular contraction
Systolic
Systolic Normal Value
110- 120 mmHg
Diastolic Normal Value
70 to 80 mmHg
pressure when ventricles relax
Diastolic
Tissue Perfusion
blood flow in tissue
cause short term changes by activation of cardiovascular centre
Neural Mechanisms
cause long term increase in blood volume and blood pressure
Endocrine Mechanisms
Baroreceptors found in:
- walls of carotid sinuses
- Aortic sinuses
- Right Atrium
Baroreceptor reflexes are triggered in response to changes in blood pressure and involve:
- vasomotor center
- cardioacceleratory and cardioinhibitory enters
Response by these centres restore normal blood pressure
Factors Affecting BP
- Cardiac Output
2. Total Peripheral Resistance (TPR)
Effect of TPR on
High Vasocontriction __________?
High Vasodilation _________?
increases BP
decrease BP
Blood Volume on BP
low volume ________?
High volume ________?
decrease BP
increase BP
Kidneys play a major role in maintaining blood pressure homeostasis by adjusting blood volume through
Urine Output
Blood Viscosity effect on BP
- Thick _____?
- Thin ______?
increase BP
decrease BP
Viscosity will change due to _______
RBC or hydration status
rising from sitting to standing causes dizziness
Orthostatic Hypotension
Low systolic (<100mmHg) and often associated with illness, poor nutrition, blood loss
Hypotension
Normal response to fever, exercise, emotional upset
Can be dangerous if chronic - silent killer
Hypertension
Substances exchange due to __________
- oxygen and nutrients leave the blood
- carbon dioxide and other wastes leaves the cells
concentration gradients
Substances take various routes entering or leaving the blood through:
- Direct diffusion through membranes
- Diffusion through intercellular clefts
- Diffusion through pores of fenestrated capillaries
- Transport via vesicles
Fluid movement at capillary level depends on difference between two pressures:
- Blood pressure force fluid and solutes out of capillaries
- Osmotic pressure draws fluid into capillaries
note: some fluid is moved into the lymph system
Is fetal Circulation is temporary or permanent?
it is temporary only in the fetus
Fetus receives exchanges of gases, nutrients, and wastes through the______
Placenta
it is a vein that carries blood rich in nutrients and oxygen to the fetus
umbilical vein
it carries carbon dioxide and debris laden blood from fetus to placenta
Umbilical arteries
in Fetal circulation, oxygenated blood bypasses the _____
liver
(Blood goes from the umbilical vein through the ductus venous and enters the inferior vena cava into the right atrium or heart (the blood in the IVC is deoxygenated, thus when the two blood mix, it is now moderately oxygenated)
Changes in circulation at birth (with first breath)
(a) the foramen ovale becomes __________, so blood now can only travel from the right atrium to the right ventricles
(b) the ductus arterioles collapses and becomes the ___________, which helps anchor the aorta beside the pulmonary trunk
a. fossa ovalis
b. ligamentum arteriosum
a simple “tube heart” develops in the embryo and pumps by week ____?
week 4
the heart becomes a four chambered organ by the end of ______week
7 weeks
this account for half of all infant death resulting congenital problems
congenital heart defects
An aging heart
decreased size
decreased contractile strength
left ventricular wall thickens
heart valves more stiff - murmurs
Age related problems with the CV system include:
- weakening of venous valves causing varicose veins
- Progressive arteriosclerosis
- Hypertension resulting from loss of elasticity of vessels
- Coronary artery disease resulting from fatty, calcified deposits in the vessels
