Circulatory System Flashcards
What are the four functions of the circulatory system?
- Movement of fluids
- Regulation of temperature
- Distribution of molecules (hormones)
- Distribution of cells (immune system)
There are two functional components to the cardiovascular system. What are they?
- The blood vascular system
- The lymphatic vascular system
What are the primary differences between the blood and lymphatic vascular systems?
The blood vascular system circulates blood vessels that are pumped by a muscular organ, the heart
The lymphatic vascular system returns and transports lymph without a central pump; smooth muscle in vessel walls move lymph in one direction
Describe the common structure of blood vessels.
- Tunica intima - inner lining with single layer of flattened epithelial cells (endothelium)
- Tunica media - middle layer, mostly muscular
- Tunica adventitia - outer layer of supporting tissue
What are vasa vasorum?
Small arteries that run in the tunica adventitia and send arterioles and capillaries into the tunica media to provide nutrient and waste exchange
What are vasa vasorum important?
Diffusion from the lumen is insufficient to provide the tunica media with nutrition and waste elimination
________________ content exhibits the greatest variation from one part of the blood vascular system to the next
Muscle content
What is blood flow influenced by?
By variation in the activity of muscle tissue
Is there muscle in capillaries?
No
Is there muscle in the heart?
Yes, it’s literally all muscle
The ____________________ is located anterior to the chest wall and connects to the great veins and artiers; it has a free apex and sits in the pericardial sac
Heart
What are the four histological characteristics of cardiac muscle tissue?
Small
Mononucleated
Branched
Intercalated discs
What are the four muscular chambers of the heart?
Left atria
Right atria
Left ventricle
Right ventricle
The ________________ pump blood to the lungers and the body; the __________________ received blood from the lungs and the body
Ventricles
Atria
Walls of all four heart chambers consist of three major walls or tunics. What are they?
- Endocardium
- Myocardium
- Epicardium
The _________________________ is a single layer of squamous endothelial cells that sits on a thin layer of loose connective tissue that contains _______________ and collagen fivers and _____________ muscle cells
Endocardium
Elastic
Smooth muscle
The ______________________ is below the endocardium and connects with the myocardium; it contains small vessels, nerves, and importantly ________________ _____________
Subendocardium
Purkinjie Fibers
The ___________________ is the thickest of tunics in the heart and consists of _________________ muscle cells; it is much thicker in the ventricles than in the atria
Myocardium
Cardiac muscle cells
Why does the myocardium have an extensive capillary network?
The high oxygen demand of the myocardium
The ___________________ is the external layer of the heart and is composed of a simple squamous epithelium (_____________________) and supported by a thin layer of connective tissue
Epicardium
Mesothelium
The thin layer of connective tissue that supports the epicardium is composed of ____________________ tissue containing _________________ fibers
Fibrocollagenous tissue
Elastic fibers
What are papillary muscles?
Attachments for chordae tendinae (AV valves)
Myocardial thickness differs in individuals who are healthy or diseased; _____________________ results from long-standing physical exertion (athletes) and pathology (i.e., hypertension)
Hypertrophy
Muscle fivers are thicker and the nuclei are ________________ and _______________ in hypertrophied myocardium
Larger
Darker
The impulse-conducting system of the heart is responsible for what?
Generating the stimulus for contraction and spreading the contraction to the myocardium
What are the three major components of the cardiac conducting system?
- Sinoatrial node
- Atrioventricular node
- Atrioventricular bundle of His
Cells and fibers of the impulse-conducting system are modificed cardiac muscle cells functionally integrated by ____________ _____________
Gap junctions
The impulse rate of the conducting system is controlled by the __________________ nervous system
Autonomic
Describe the steps of the impulse-conducting system of the heart.
- The SA node in the right atrium generates the impulse
- The impulse spreads to the AV node in the right atrium
- The impulse is passed along the conducting fibers of the AV bundle of His, which divide into the left and right bundle branches that become the Purkinjie Fibers
What are the steps of the impulse conducting system?
The atrioventricular bundle of His splits into the left and right _______________ _____________ that become the ______________ ___________ that run beneath the endocardium and penetrate the myocardium
Bundle branches
Purkinjie fibers
The bundle branches are separated from myocardial fibers by a ______________ layer; they are specialized conducting fibers that contain few myofibrils and abundant ________________ granules and _______________
Fibrous
Glycogen
Mitochondria
_______________ _________________ are the terminal branches of the AV bundle branches located in the subendocardial connective tissue
Purkinjie fibers
What are the histological and structural characteristics of Purkinjie fibers?
Purkinjie fibers are large modified cardiac muscle fibers that cluster together in groups with one to two nuclei per cell
They contain a pale-staining central area with red stains on the cell periphery representative of myofibrils
Do Purkinjie fiber contain T-tubules and intercalated discs? If not, how do they communicate and connect with each other?
No, they are connected by desmosomes and gap junctions
The heart has four valves. What are they?
- The mitral valve
- The tricuspid valve
- The aortic valve
- The pulmonary valve
The mitral and tricuspid valves control blood flow from the ______________ to the _____________
Atria
Ventricles
The aortic and pulmonary valves control blood flow out of the _________________
Ventricles
______________ ______________ can be thought of as double-sided flattenings of the basic cardiovascular histological layers with different histological profiles to match their different physiological roles
Heart valves
What are the specialized features of heart valves?
They are primarily composed of a tough, specialized tunica intima in the absence of other vascular layers; the endothelium is continuyous with that of the cardiac wall while the collagenous layer toughens and becomes highly fibrous
Heart valves are primarily composed of a tough, specialized ______________ ____________ in the absence of other vascular layers; the ______________is continuous with that of the cardiac wall while the _______________ layer toughens and becomes highly ________________
Tunica intima
Endothelium
Collagenous
Fibrous