The Heart pt. 2 Flashcards
What is Cardiac Output
The amount of blood pumped out of each ventricle in a minute
Cardiac output formula
Heart Rate x Stroke Volume = CO
Factors of Heart Rate
Neural (ANS) control - Sympathetic divison increases it, Parasympathetic division slows it
Hormones and Ions - epinephrine + thyroxine increases
Physical Factors - Age, gender, body temp
What is stroke volume
The volume of blood pumped out left ventricle, 70 ml blood per heartbeat
Stroke Volume factors
Preload - how much cardiac muscle cells are stretched before contracting
Contractibility - ability of cardiac muscles to generate tension
Afterload - amount of pressure ventricles must overcome to eject
Blood Vessels: Arteries
Carry blood away from the heart, all oxygenated (except pulmonary trunk/arteries). Thick walls, Aorta is the largest
Blood Vessels: Arterioles
Feeds the capillary beds
Blood Vessels: Capillary Beds
In tissues, connects small arterioles to small venules
Blood Vessels: Venules
Drain capillary beds
Blood Vessels: Veins
Drains tissues and returns blood to heart, all are deoxygenated except pulmonary veins. Thin walla
Blood Vessels: Great veins
Superior and inferior vena cava, entering the right atrium
Which arteries supply the Cerebrum
Internal carotid arteries divide into anterior cerebral artery + the middle cerebral artery to supply cerebrum
Which arteries supply the Brain stem and cerebellum
Paired vertebral arteries that form basilar artery
Which arteries supply the posterior part of cerebrum
Basilar artery divides to form posterior cerebral arteries
What is the circle of willis?
Anterior and posterior blood supplies unite by small arterial branches, forming circle of willis.
What is the Hepatic Portal Circulation
Drains venous blood from digestive organs, delivers nutrient rich blood to liver through hepatic portal vein
How does the Hepatic Portal Circulation help the liver
Allows liver to process substances before reaching system circulation, liver will detoxify blood of any drugs and will remove nutrients to store and later release into blood
What is arterial Pulse
The pressure wave in arterial system caused by alternating expansion and recoil of an artery with each left ventricle contraction
Average pulse rate
70-76 bpm
What is blood pressure
The pressure that blood exerts against inner walls of blood vessels, is the force that keeps blood circulating continuously.
How to measure blood pressure
Systolic blood pressure - pressure in arteries at peak ventricle contraction (top #)
Diastolic blood pressure - pressure in arteries when ventricles are relaxing (bottom #)
Eg. 120/80 mmHg
What is hypotension
A systolic blood pressure below 100 mmHG
What is hypertension
Sustained elevated arterial blood pressure of 140/90 or higher
Normal blood pressure rates
110-140 systolic, 75-80 diastolic
First step of capillary exchange of gases + Nutrients
Direct diffusion through the plasma membrane
Lipid- soluable substances + gases diffuse directly though the capillary wall
Second step of capillary exchange od gases + Nutrients
Diffusion through intercellular clefts (gaps between cells)
Third step of capillary exchange od gases + Nutrients
Diffusion through pores
Fenestrated capillaries (capillaries w pores) allow free passage of small solutes and fluids. Found where absorption occurs
Fourth step of capillary exchange od gases + Nutrients
Transport via vesicles
Some lipid-insoluble substances may enter or leave the blood
