Peripheral circulation & regulation of blood flow With 100% accurate solutions

the circulation of the blood in the smallest blood vessels, the microvessels of the microvasculature present within organ tissues. The microvessels include terminal arterioles, metarterioles, capillaries, and venules

what is the structure and function of microcirculation

The primary role of the lymphatic system is to return lymph to the circulation.

circulation of immune cells

filtration of debris, pathogens, cancer cells

absorption of lipids from the digestive system and transport to the blood

transport of antigen-presenting cells to lymph nodes

what is the function of lymphatic system

high levels of Pc (capillary hydrostatic pressure)

low levels of π c (capillary oncotic pressure)

high levels of K f (hydraulic conductance)

Impaired lymphatic drainage

what causes edema

Reactive hyperemia-when the heart muscle contracts (dilates) results in overshoot of blood flow

Active hyperemia- matabolites being produced

Myogenic regulation-increased perfusion pressure

Extrinsic regulation- involves vasoconstriction

what are the different ways blood flow is regulated

Short-term regulation of arterial blood pressure is dominated by the baroreceptor mechanism, whereby pressure is sensed by both cardio-pulmonary nerve endings and stretch-sensitive cells in renal afferent arterioles

Describe the short term regulation of arterial blood pressure

long term regulation of blood pressure

Accomplished through mechanisms that control blood volume through neural and humoral pathways.

Consists of Angiotensin II-has direct effects on sodium retention by the kidney. This describes:

Global cerebral blood flow is under the control of arterial PCO2

Flow below 35 mL/100g of brain/min causes neuronal dysfunction. In a normal individual, cerebral blood flow is maintained at a constant level of 50 mL/100g/min for MAPs between 50 - 150 mmHg. Blood flow is autoregulated.

List the unique features of cerebral circulation

-Compression of the coronary circulation caused by contraction of myocardium.

-During isovolumetric contraction, left coronary flow rapidly decreases.

-With the onset of isovolumetric relaxation, left coronary artery flow increases.

-Powerful metabolic vasodilation during diastole.

List the unique features of coronary circulations

pulmonary vascular resistance is high. Pressure is higher on right side of the heart, thus forcing the blood to the left side.

List the unique features of fetal circulation

involves changes in CO and regional resistances

TPR is reduced so that exercise is associated with high CO and low resistance.

Describe the regulation of arterial blood pressure during exercise. hemorrhage or standing

tunica intima, tunica media, tunica adventitia

List the structures of arteries and veins

Tunica adventitia

tissues layer consisting mainly of connective tissue

Tunica intima

innermost layer consisting of a single layer of endothelial cells

Tunica media

tissue layer comprised mostly of smooth muscle and is the contractile portion

thoracic duct; lymphatic duct.

Lymph is ultimately returned into the central venous circulation through the _______________ and __________________.

smooth muscle cell, collecting lymphatic, valve, lymphatic capillary, interstitial fluid

What does the stucture of the lymphatic vessel consist of

nitric oxide synthase (NOS)

Endothelium-dependent vasodilators such as acetylcholine (Ach), histamine, and bradykinin activate ___________________________.

the production of NO (nitric oxide)

What does the activation of NOS result in?

Thromboxane A2

opposes prostacyclin and is a potent prothrombotic substance and vasoconstrictor that is important in inflammation.

Endothelin-powerful vasoconstrictor protein released by endothelial cells when vessels are damaged

Angiotensin II and Vasopressin- are important long-term regulators of vascular control

NO is released by shear stress in vasoconstrictors is a form of vascular control as follows:

Active hyperemia

refers to the increase in blood flow that occurs in tissues when metabolism is elevated; vasodilation enhances flow. For example, during exercise

Autoregulation

can occur without changes in local metabolism due to the myogenic hypothesis - smooth muscle cells constrict in response to elevated transmural pressure.

a-Receptors -cause vasoconstriction

b2-Receptors -create vasodilation via cAMP

Name the two types of adrenergic receptors in smooth muscles

activate chemoreceptors

Aortic and carotid bodies respond to reduced PO2, elevated CO2, and elevated H+. They function to

Circle of Willis

The cerebral circulation is supplied by the arterial ____________________, which is derived from the internal carotid and the vertebral arteries.

Central nervous system ischemic reflex

the vasomotor center in the medulla becomes ischemic, strong sympathetic outflow will increase BP above cerebral blood flow auto-regulatory range

cushing reflex

A raise in arterial pressure is generated by sympathetic outflow in an attempt to overcome high intracranial pressure that is impeding blood flow (usually associated with traumatic head injury)

Foramen ovale

shunts blood from the right to the left atrium, bypassing the right ventricle and pulmonary circulation

Ductus arteriosus

another right-to-left shunt between the pulmonary artery and the aorta