Cardiovascular System

Cardiovascular System Advanced Biology Spring 2013

Vocabulary Development • Angio- vessel • Ather- porridge • Brady- slow • Diastol- dilation • Edem- swelling • Gram- something written • Lun- moon • Myo- muscle • Papill- nipple • Phleb- vein • Scler- hard • Syn- together • Systol- contraction • Tachy- rapid

Introduction • Cardiovascular system- all blood vessels, capillaries, veins, arteries, & heart make up the cardiovascular system • Blood vessels form 2 circuits: • Pulmonary circuit- sends oxygen poor blood to the lungs to pick up oxygen & unload carbon dioxide • Systemic circuit- sends oxygen rich blood & nutrients to all body cells & removes wastes

Structure of the Heart • Size & Location of the Heart • Size varies with body size (average adult: 14 cm long & 9 cm wide) • Inside the thorax • Rests on the diaphragm

Structure of the Heart • Coverings of the Heart • Pericardium- encloses the heart & the proximal ends of the large vessels that are attached to it • Fibrous pericardium- outer fibrous layer that protects the double layered serous membrane • Parietal pericardium- inner lining of the fibrous pericardium • Visceral pericardium- inner most layer of the double membrane & directly covers the heart muscle • Pericardial cavity- space between the parietal & visceral pericardia filled with fluid

Structure of the Heart • Wall of the Heart • 3 distinct layers: • Epicardium- outer layer • Protects the heart by reducing friction • Serous membrane consists of connective tissue • Includes capillaries & nerve fibers • Myocardium- middle layer • Thick & consists mostly of cardiac muscle tissue that pumps blood out of the heart chambers • Endocardium- inner layer • Consists of epithelium & underlying tissue • Contains blood vessels & specialized cardiac muscle fibers called Purkinje fibers • Lines all chambers of the heart & covers the structures that project into them

Structure of the Heart • Heart Chambers & Valves • Divided into 4 hollow chambers; 2 left & 2 right • Atria- upper chambers • Thin walls • Receive blood returning to the heart • Auricles- small projections of the atria that increase atrial volume slightly • Right & left atrias are separated by the interatrial septum • Ventricles- lower chambers • Force blood out of the heart into arteries • Right & left ventricles are separated by the interventricular septum • Ventricles & atria on each side of the heart are separated by atrioventricular orifice which is guarded by an AV valve (atrioventricular valve)

Structure of the Heart • Heart Chambers & Valves • Right atrium • Receives blood from 2 large veins: superior vena cava & inferior vena cava • Both return blood low in oxygen from tissues • Coronary sinus- drains blood into the right atrium from the myocardium of the heart • Right atrium is separated from the right ventricle by a tricuspid valve (right atrioventricular valve) • Allows blood to flow from the right atrium into the right ventricle but not in the other direction

Structure of the Heart • Heart Chambers & Valves • Right Ventricle • Thinner muscular wall than the left ventricle • Pumps blood short distance through the pulmonary trunk which divides into the left & right pulmonary arteries that lead to the lungs • Pulmonary valve is at the base of the trunk (pulmonary semilunar valve) & prevents blood from flowing back in the right ventricle from the pulmonary trunk

Structure of the Heart • Heart Chambers & Valves • Left atrium • Receives blood from 4 pulmonary veins (2 from each lung) • Blood passes from the left atrium to the left ventricle through the atrioventricular orifice through a mitral valve (bicuspid valve; left atrioventricular valve) • Prevents blood from flowing back into the left atrium from the left ventricle

Structure of the Heart • Heart Chambers & Valves • Left Ventricle • Contracts & sends blood through the aorta which branches out and sends blood to all parts of the body • Aortic valve (aortic semilunar valve; tricuspid) • opens to allow blood to leave the left ventricle but not to go back into the left ventricle • Mitral & tricuspid valves are also called atrioventricular valves because they are between the atria and ventricles • Pulmonary & aortic valves are called semilunar valves because of the half-moon shaped cusps

Path of Blood Through the Heart • Blood from systemic circuits • Venaecavae & coronary sinus • Right atrium • Through tricuspid valve • Right ventricle • Through pulmonary valve • Pulmonary trunk • Pulmonary arteries • Alveolar capillaries (lungs) • Pulmonary veins • Left atrium • Through mitral valve • Left ventricle • Aortic valve • Blood to the systemic circuit

Blood Supply to the Heart Cardiac Veins Coronary sinus Right atrium

Heart Actions • Actions are regulated so that… • Atria contract, atrial systole, while the ventricles relax, ventricular diastole • Ventricles contract, ventricular systole, while the atria relax, atrial diastole • Both atria & ventricles relax for a brief moment • These actions make up a complete heartbeat and is called the cardiac cycle

Heart Actions • Cardiac Cycle • Changes in pressure in the heart chambers during a cardiac cycle cause valves to open & close • During ventricular diastole (atrial systole) the pressure difference between atria & ventricles opens the AV valves allowing the ventricles to fill • During ventricular systole (atrial diastole) the AV valves are closed, atria are relaxed and blood flows back into the atria as the ventricles contract

Blood Vessels • Form a closed circuit of tubes that carries blood from the heart to the body cells and back • Includes: • Arteries • Arterioles • Capillaries • Venules • Veins

Blood Vessels • Arteries & arterioles conduct blood away from the ventricles of the heart & lead to capillaries • Arteries- carry blood at high pressure • Arterioles- arteries sub divide into progressively thinner tubes & give rise to arterioles • Capillaries- smallest-diameter blood vessels, connect the smallest arterioles & venules • Venules & veins return blood from the capillaries to the atria • Venules- microscopic vessels that come from capillaries and merge to form veins • Veins- carry blood back to the atria & follow pathways similar to the arteries

Paths of Circulation • Pulmonary circuit- consists of vessels that carry blood from the heart to the lungs and back to the heart • Systemic circuit- carries blood from the heart to all other parts of the body and back again & include coronary circulation

Paths of Circulation • Pulmonary Circuit • Pulmonary trunk of right ventricle • Pulmonary trunk is divided into the left & right pulmonary arteries, which enter the right & left lungs • Lobar Branches • 3 in right • 2 in left • Lobar branches divide into arterioles • Arterioles divide into networks of capillaries • Alveolar capillaries exchange gases between the blood & air • Taking out carbon dioxide and putting in oxygen

Paths of Circulation • Pulmonary Circuit cont… • Pulmonary venules • Alveolar capillaries send oxygen rich blood here • Pulmonary venules join to form smalls veins • Small veins join to form the 4 pulmonary veins return blood to the left atrium • 2 from each lung

Paths of Circulation • Systemic Circuit • Freshly oxygenated blood moves from the left atrium to the left ventricle • Left ventricle contracts pushing blood into the aorta, which branches out and sends oxygenated blood to all of the body tissues • Left ventricle contraction is also responsible for the force that returns blood to the right atrium to start the pulmonary circuit

Arterial System • Aorta • Largest diameter artery in the body • Extends upward from the left ventricle & arches over the heart to the left & descends just in front of and to the left of the vertebral column • several branches

Arterial System • Principal Branches of the Aorta • Ascending aorta- part of the aorta that sends blood up; first part of the aorta • Aortic sinus- swelling in the aortic wall, behind each cusp of the aortic valve • Right & left coronary arteries begin here • Includes the arch of the aorta

Arterial System • Arch of the Aorta • 3 major branches of the ascending aorta • Brachiocephalic- supplies blood to the tissues of the upper limb & head • Divides into: • Right common carotid artery- carries blood to the right side of the neck and head • Right subclavian artery- carries blood to the right arm • Left Common Carotid- carries blood to the left side of the neck • Left Subclavian Artery- carries blood to the left arm

Arterial System • Descending Aorta • Directly in front of the vertebral column • Thoracic aorta- part of the descending aorta above the diaphragm • Branches include: • Bronchial artery- supplies blood to the bronchi • Pericardial artery- supplies blood to the pericardium • Esophogeal artery- supplies blood to the esophagus • Mediastinal artery- supplies blood to the mediastinum (area above the diaphragm surrounding the heart and lungs) • Posterior intercostal artery- supplies blood to the thoracic wall • Abdominal aorta- part of the descending aorta that is below the diaphragm • Divides into several different arteries

Arterial System • Branches of the Abdominal Aorta • Celiac artery- supplies organs of the upper digestive tract • Splits into gastric, splenic, and hepatic arteries • Phrenic artery- supplies the diaphragm • Superior mesenteric artery - supplies portions of the small & large intestines • Suprarenal artery- supplies the adrenal glands • Renal artery- supplies the kidney • Gonadal artery- supplies the ovaries or testes • Inferior mesenteric artery- supplies the lower portion of the large intestine • Lumbar arteries- supply the posterior abdominal wall • Middle sacral artery- supplies the sacrum & coccyx • Common iliac artery- supplies the lower abdominal wall, pelvic organs, and lower limb

Arterial System • Arteries to the Brain, Head, & Neck • Branches of the subclavian & common carotid arteries supply blood to the structures of the head, brain, and neck • Vertebral arteries – come from the subclavian arteries • Basilar artery- runs along the ventral brainstem & branches out leading to the pons, midbrain, & cerebellum • Posterior cerebral arteries- supplies parts of the occipital & temporal lobes of the cerebrum • Thyrocervical arteries- branches and supplies blood to thyroid gland, parathyroid glands, larynx, trachea, esophogus, & pharynx • Costcocervical arteries- supply blood to muscles in the neck, back, & thoracic wall

Arterial System • Arteries of the Head, Neck, & Brain cont… • Common carotid arteries divide to form internal & external carotid articles • External Carotid Artery • Upward on the side of the head & branches out to structures in the neck, face, jaw, scalp, & base of the skull • Main vessels of the external carotid artery • Superior thyroid artery- hyoid bone, larynx, thyroid gland • Lingual artery- tongue, muscles of the tongue, salivary glands beneath the tongue • Facial artery- pharynx, palate, chin, lips, nose • Occipital artery- scalp on the back of the skull, the meninges, mastoid process, muscles of the neck • Posterior auricular artery- ear & scalp over the ear • Terminates by dividing into maxillary & superficial temporal arteries

Arterial System • Arteries of the Head, Neck, & Brain cont… • Internal Carotid Artery • Provides the major blood supply to the brain • Major branches: • Ophthalmic artery- supplies the eyeball & muscles & accessory organs associated with the orbit • Posterior communicating artery- forms part of the cerebral arterial circle • Anterior choroid artery- supplies the choroid plexus within the lateral ventricle of the brain & to nerve structures of the brain • Terminates by dividing into the anterior & middle cerebral arteries

Arterial System • Arteries to the Shoulder & Upper Limb • Subclavian artery passes through the first rib and clavicle and turns into the axillary artery • Axillary artery- supplies branches to structures in the axilla & chest wall, part of the mammary gland, the upper end of the humerus, the shoulder joint, muscles in the back, shoulder, & chest • Turns into the brachial artery when it leaves the axilla • Brachial artery- along the humerus to the elbow; supplies the triceps and other muscles in the upper arm • Branches at the elbow into the radial & ulnar arteries

Arterial System • Arteries of the Shoulder & Upper Limb cont… • Ulnar artery- travels down the ulnar side of the forearm to the wrist; supply blood to the flexor and extensor muscles in the forearm • Radial artery- continuation of the brachial artery, travels down the radial side of the forearm to the wrist; supplies the lateral muscles of the forearm

Arterial System • Arteries of the Thoracic & Abdominal Walls • Branches from the subclavian artery and the thoracic aorta feed the thoracic & abdominal walls • Internal thoracic artery- originates in the base of the neck and passes downward behind the upper six ribs • Branches in to 2 anterior costal arteries at each rib • Anterior costal arteries- supply the intercostal muscles • Posterior intercostal arteries- branch from the thoracic aorta & supply the intercostal muscles, the vertebrae, the spinal cord, & deep muscles of the back

Arterial System • Arteries of the Pelvis & Lower Limb • Common iliac arteries- branch from the abdominal aorta at the pelvic brim & supply blood to the pelvic organs, gluteal regions, & lower limbs • Descend & divide into internal & external branches • Internal iliac artery branches include: • Iliolumbar artery- supplies the ilium & muscles of the back • Superior & inferior gluteal arteries- supplies the gluteal muscles, pelvic muscles, & skin of the buttocks • Internal pudendal artery- supplies the alimentary canal, the external genitalia, & the hip joint • Superior & inferior vesicular arteries- supplies the urinary bladder & in males also the supply the seminal vesicles & prostate gland • Middle rectal artery- supplies the rectum • Uterine artery- supplies the uterus & vagina

Arterial System • Arteries of the Pelvis & Lower Limb cont… • External iliac artery- provides the main blood supply to the lower limb • 2 large branches: inferior epigastric artery & deep circumflex iliac artery • Supply the muscles & skin in the lower abdominal wall • Femoral artery- has many branches • Superficial circumflex iliac artery- supplies lymph nodes & skin of the groin • Superficial epigastric artery- supplies the skin of the lower abdominal wall • Deep femoral artery- supplies the hip joint & muscles of the thigh; largest branch of the femoral artery • Deep genicular artery- supplies the distal ends of thigh muscles & the anastomosis around the knee joint

Arterial System • Arteries of the Pelvis & Lower Limb • Popliteal artery- supply blood to the knee joint & to certain muscles in the thigh & calf • Femoral artery becomes the popliteal artery • Anterior tibial artery- runs between the tibia & fibula & supplies the skin & muscles in the anterior & lateral regions of the leg • Posterior tibial artery- beneath the calf muscle & supplies the skin, muscles, & other tissues of the lower leg • Medial & lateral plantar arteries-supply the instep, heel, & toes • Fibular artery- extends downward along the fibula

Cardiovascular System