Biomedical Science - Blood, heart & vessels

The Circulatory system is made up of

cardiovascular system & lymphatic system

The cardiovascular system

the heart and blood vessels transport blood through the pulmonary circulation (lungs) and the systemic circulation (head and body)

The lymphatic system

lymph vessels transport excess fluid from body tissues toward the heart (one direction only)

Blood components

plasma, cells, platelets

Plasma

water, plasma protein eg albumin, ions, glucose, AA, hormones, gases, waste products

Blood is an important transport system for

oxygen, hormones, ions, nutrients, heat, WBC, clotting

Location of the heart

thoracic cavity, mediastinal space, posterior to sternum, medial to both lungs, anterior to vertebral column

Blood flow through heart

1 Right atrium receives blood from body, 2 Right ventricle pumps blood to lungs, 3 Left atrium receives blood from lungs, 4 Left ventricle pumps blood to body

when do valves open and close

in response to pressure of blood as it moves through heart

how to valves prevent backflow

create unidirectional blood flow

Valves

tricuspid, pulmonary, bicuspid, aortic

Arteries carry

oxygenated blood EXCEPT pulmonary artery

Veins carry

deoxygenated blood EXCEPT pulmonary vein

which part of the heart has the thickest wall

L ventricle, pumps blood to whole body

Parts of the aorta

aortic arch, thoracic aorta, abdominal aorta

Aortic arch

curves over the heart, giving rise to branches that bring blood to the head, neck, and arms

Thoracic aorta

travels down through the chest

Abdominal aorta

begins at the diaphragm, dividing into R and L iliac arteries

most organs receive blood from a branch of

descending aorta

Blood supply to the brain

R and L common carotid arteries (side of neck) branch into internal carotid arteries (go inside the skull to supply brain) and the external carotid (stay outside the skull to supply face, head and neck && The posterior of brain supplied by the vertebral arteries that branch off the subclavian artery

The Sino Atrial Node (SAN)

Natural pacemaker, Fires impulses steadily 60-80 bpm at rest, First causes contraction of the atria, followed by a contraction of the ventricles

Contraction

systole

Relaxation

diastole

When do atrioventricular valves open

when pressure in atria > ventricles

When do atrioventricular valves shut

when pressure in ventricles > atria

Nervous system control of HR

Sympathetic NS speeds up heart rate (sympathetic cardiac nerves) & Parasympathetic NS can slow down heart rate (vagus nerve)

LUB sound

AV valves shutting

DUB sound

SL valves shutting