ch.19 learning outcomes

Describe the pulmonary circuit.

Describe the pulmonary circuit.

Responsible for carrying deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart. It involves the right side of the heart pumping blood to the lungs for oxygenation and the left side of the heart receiving oxygenated blood from the lungs.

Describe the systemic circuit.

Part of the circulatory system that carries oxygenated blood from the heart to the body's tissues and organs, then returns deoxygenated blood back to the heart.

Which chamber of the heart receives blood from the systemic circuit?

The right atrium.

Efferent vessels.

Carry blood away from the heart:

• arteries

Afferent vessels.

Bring blood towards the heart:

• veins

List the 5 classes of blood vessels along with their structures and functions.

• Arteries: Thick-walled, carry blood away from the heart.

• Arterioles: Smaller branches of arteries, regulate blood flow.

• Capillaries: Thin-walled, site of nutrient and gas exchange.

• Venules: Collect blood from capillaries.

• Veins: Thin-walled, carry blood back to the heart.

Describe a capillary.

A tiny blood vessel with thin walls that allows for the exchange of nutrients, gases, and waste products between blood and tissues.

Describe the structures of capillaries and their functions in the exchange of dissolved materials between blood and interstitial fluid.

• Structures:

  • Single layer of endothelial cells

  • Thin walls for easy diffusion

  • Narrow lumen for close contact

• Functions in Exchange:

  • Facilitate diffusion of nutrients, gases, waste

  • Allow exchange of oxygen, carbon dioxide

  • Aid in maintaining fluid balance

The two types of capillaries with a complete endothelium.

Continuous and fenestrated.

Continuous capillaries.

Endothelial cells form a continuous lining with tight junctions. Facilitate exchange of nutrients, gases, and waste between blood and tissues.

Fenestrated capillaries.

Small blood vessels with pores in their endothelial cells, allowing for rapid exchange of fluids and small molecules.

At what sites of the body are fenestrated capillaries located?

Where rapid exchange of substances is necessary, such as the kidneys, intestines, and endocrine glands.

Describe the venous system, and indicate the distribution of blood within the cardiovascular system.

The venous system consists of veins that carry deoxygenated blood back to the heart. Blood is distributed throughout the cardiovascular system via arteries, capillaries, and veins.

Why are valves located in the veins but not arteries?

To prevent backflow of blood due to lower pressure, while arteries have thicker walls to withstand higher pressure without needing valves.

How is blood pressure mainlined in the veins against the force of gravity?

• Valves preventing backflow

• Muscle contractions squeezing veins

• Respiratory movements aiding blood return

• Sympathetic nervous system constriction

Describe the distribution of total blood volume in the body.

• Heart and Pulmonary Circulation: 9%

• Systemic Arteries: 13%

• Systemic Capillaries: 7%

• Systemic Veins: 64%

• Systemic Venous System: 7%

What factors are involved in the formation of varicose veins?

Can be caused by factors such as genetics, age, obesity, pregnancy, prolonged standing, and a sedentary lifestyle.

Varicose veins.

Are enlarged, twisted veins that usually occur in the legs. They can be caused by weakened valves and walls in the veins, leading to blood pooling and increased pressure, resulting in the characteristic appearance of varicose veins.

Explain the roles of pressure, resistance, and venous return in cardiac output.

• Pressure: Pressure difference drives blood flow through the circulatory system.

• Resistance: opposes blood flow, affecting cardiac output.

• Venous Return: the blood flow returning to the heart

Neural and endocrine regulatory mechanisms influence which factors?

• Heart rate

• Contractility

• Vascular tone

Which is greater: arterial pressure or venous pressure?

Arterial pressure is greater since they

• Carry blood away from the heart under higher pressure to deliver oxygen and nutrients to tissues efficiently

Why is it beneficial for capillary pressure to be very low?

Prevents damage to delicate capillaries and reduces fluid leakage into tissues.

List the factors that contribute to total peripheral resistance.

• Vessel radius

• Vessel length

• Blood viscosity

Explain the 1/r4 equation.

Describes how resistance in blood vessels increases significantly as the radius of the vessel decreases. This relationship is based on Poiseuille's Law and highlights the importance of vessel diameter in regulating blood flow.

Which would reduce the peripheral resistance: an increase in vessel length or an increase in vessel diameter?

• Increase in vessel diameter

  • Reduces peripheral resistance due to decreased friction against the vessel walls, allowing blood to flow more easily.

Define blood flow and describe its relationship to blood pressure and peripheral resistance.

• Refers to the movement of blood through the circulatory system.

• It is directly proportional to blood pressure and inversely proportional to peripheral resistance.

  • BP increases = BF increases

  • PR increases = BF decreases

In a healthy person, where is blood pressure greater: in the aorta or inferior vena cava? Explain your answer.

• Blood pressure is greater in the aorta than in the inferior vena cava.

  • The aorta receives blood directly from the heart's left ventricle, leading to higher pressure compared to the vena cava, which returns blood to the heart.

Calculate the mean arterial pressure for a person whose blood pressure is 125/70.

MAP = diastolic pressure + 1/3(systolic pressure - diastolic pressure).

For a blood pressure of 125/70, MAP = 70 + 1/3(125 - 70) = 85 mmHg.

Discuss the movement of fluids between capillaries and interstitial spaces.

Fluid movement between capillaries and interstitial spaces occurs through processes like diffusion, filtration, and osmosis. This movement is essential for maintaining homeostasis in the body.

Under what general conditions would fluid move into a capillary?

Having a higher hydrostatic pressure in the capillary compared to the surrounding interstitial fluid. This pressure difference allows fluid to be pushed into the capillary through the capillary walls.

Define edema.

The abnormal accumulation of fluid in interstitial spaces, leading to swelling of tissues. It can be caused by various factors such as inflammation, injury, or medical conditions.

Identify the conditions that would shift the balance between hydrostatic and osmotic forces.

• Changes in blood pressure

• Protein levels

• Permeability of capillaries.

Explain central regulation, autoregulation, and baroreceptor reflexes in response to changes in blood pressure and blood composition.

• Central regulation involves the brain controlling blood pressure through the autonomic nervous system.

• Autoregulation refers to local tissues adjusting their blood flow based on metabolic needs.

• Baroreceptor reflexes involve sensors detecting changes in blood pressure and signaling adjustments to maintain homeostasis.

Define tissue perfusion.

Refers to the process of blood flow through tissues, providing oxygen and nutrients while removing waste products. It is essential for cellular function and overall health.

Describe autoregulation as it relates to cardiovascular function.

Refers to the ability of blood vessels to maintain constant blood flow despite changes in blood pressure. This process ensures organs receive adequate blood supply.

Explain the function of baroreceptor reflexes.

Help regulate blood pressure by sensing changes in pressure and sending signals to the brain to adjust heart rate and blood vessel diameter to maintain homeostasis.

Explain the hormonal regulation of blood pressure and blood volume.

Help regulate blood pressure and volume by controlling water reabsorption, sodium levels, and blood vessel constriction.

Identify the hormones responsible for short term regulation of decreasing blood pressure and volume.

• Antidiuretic hormone (ADH): Acts on kidneys to retain water.

• Aldosterone: Increases sodium reabsorption to retain water and increase blood volume.

How does the kidney respond to vasoconstriction of the renal artery?

By activating the renin-angiotensin-aldosterone system, leading to increased blood pressure and sodium retention.

Describe the role of natriuretic peptides.

Regulating blood pressure and fluid balance by promoting vasodilation, increasing urine production, and reducing sodium reabsorption in the kidneys.

Describe the role of chemoreceptor reflexes in adjusting cardiovascular activity.

Detect changes in blood chemistry, like oxygen and carbon dioxide levels. They help regulate heart rate and blood pressure to maintain homeostasis.

Where are chemoreceptors located?

Located in the carotid bodies and aortic bodies, which are specialized structures in the arteries that detect changes in blood chemistry, such as oxygen levels, carbon dioxide levels, and pH.

What is the function of chemoreceptor reflexes?

Help regulate respiratory rate and depth in response to changes in blood levels of oxygen, carbon dioxide, and pH.

What effect does an increase in the respiratory rate have on Co2 levels?

It decreases CO2 levels. When breathing faster, more CO2 is exhaled, reducing its concentration in the blood, leading to respiratory alkalosis.

Explain how the cardiovascular system responds to the demands of exercise.

By increasing heart rate, cardiac output, and blood flow to muscles, delivering more oxygen and nutrients for energy production. Additionally, blood vessels dilate to enhance circulation and remove waste products efficiently.

Describe the respiratory pump.

A mechanism that aids in the circulation of blood by using changes in pressure during breathing to help move blood through the veins towards the heart.

Describe the changes in cardiac output and blood flow during exercise.

• Cardiac output increases due to higher heart rate and stroke volume.

• Blood flow to muscles increases to meet oxygen demand.

  • Blood flow to non-essential organs decreases.

Explain the body’s response to blood loss.

Involves vasoconstriction to reduce blood flow, increased heart rate to maintain blood pressure, and activation of the coagulation cascade to stop bleeding.

Identify the compensatory mechanisms that respond to blood loss.

• Baroreceptor Reflex: Activates to maintain blood pressure.

• Renin-Angiotensin-Aldosterone System: Increases fluid retention.

• Sympathetic Nervous System Activation: Constricts blood vessels to maintain perfusion.

• Erythropoiesis Stimulation: Increases red blood cell production.

Name the immediate and long -term problems related to hemorrhage.

• Immediate Problems:

  • Hypovolemic shock

  • Decreased tissue perfusion

  • Organ dysfunction

• Long-Term Problems:

  • Anemia

  • Infection

  • Organ damage due to prolonged hypoperfusion

Describe circulatory shock.

A life-threatening condition where blood flow is inadequate to meet the body's needs, leading to organ damage. It can be caused by various factors such as severe blood loss, infection, or heart failure.

Describe progressive shock.

A stage of shock where the body's compensatory mechanisms begin to fail, leading to worsening hypoperfusion and organ dysfunction. It is characterized by a decrease in blood pressure, increased heart rate, altered mental status, and inadequate tissue perfusion.

Describe irreversible shock.

A state where the body's vital organs suffer such damage that even if the initial cause of shock is corrected, the organs cannot recover, leading to death.

Vasculogenesis.

Formation of new blood vessels from endothelial cell precursors.

Angiogenesis

Growth of new blood vessels from existing ones.

What cells do vasculogenesis form?

Blood vessels from mesodermal cells called angioblasts.

What cells do angiogenesis form?

Blood vessels from existing blood vessels through sprouting and remodeling.

Blood Islands

Clusters of angioblasts that give rise to blood vessels during embryonic development.

What is the function of hemangioblasts?

Multipotent stem cells that give rise to both blood and blood vessels. They play a crucial role in the development of the circulatory system.

Identify the major arteries and veins of the pulmonary circuit, and name the areas each serves.

• Major Arteries:

  • Pulmonary Trunk: Carries deoxygenated blood from the right ventricle to the lungs.

• Major Veins:

  • Pulmonary Veins: Carry oxygenated blood from the lungs to the left atrium.

Compare the oxygen content in the two circulatory outlets.

The difference in oxygen saturation levels in the blood leaving the heart through the pulmonary artery and the aorta.

Briefly describe general patterns of blood vessel organization.

• Arteries carry blood away from the heart.

• Veins return blood to the heart.

• Capillaries connect arteries and veins.

• Blood flows from arteries to capillaries to veins.

• Arteries have thick walls, veins have valves to prevent backflow.

Trace a drop of blood through the lungs, beginning at the right ventricle and ending at the left atrium.

• Right ventricle

• Pulmonary artery

• Lungs (oxygenation)

• Pulmonary vein

• Left atrium

Identify the major arteries and veins of the systemic circuit, and name the areas each serves.

• Major Arteries:

  • Aorta: Supplies oxygenated blood to the body.

  • Coronary Arteries: Supply blood to the heart muscle.

  • Renal Arteries: Supply blood to the kidneys.

• Major Veins:

  • Superior Vena Cava: Drains blood from upper body to heart.

  • Inferior Vena Cava: Drains blood from lower body to heart.

Identify the largest artery of the body.

The aorta.

Name the two large veins that collect blood from the systemic circuit.

Superior vena cava and Inferior vena cava.

Besides containing valves, cite another major difference between the arterial and venous systems.

The pressure they carry:

• Arteries carry blood away from the heart under high pressure, while veins carry blood back to the heart under lower pressure.

Identify the branches of the aortic arch and name the areas each serves.

• Brachiocephalic artery: Serves the right arm and head.

• Left common carotid artery: Supplies blood to the left side of the head and neck.

• Left subclavian artery: Provides blood to the left arm and chest.

Identify the branches of the superior vena cava and name the areas each serves.

• Right brachiocephalic vein (serves right arm and head)

• Left brachiocephalic vein (serves left arm and head)

Name the two arteries formed by the division of the brachiocephalic trunk.

• Right subclavian artery

• Right common carotid artery

A blockage of which branch of the aortic arch would interfere with the blood flow to the left arm?

The subclavian left artery.

Whenever Thor gets angry, a large vein bulges in the lateral region of his neck. Which vein is this?

The External Jugular Vein.

Identify the branches of the carotid arteries and name the areas each serves.

• External Carotid Artery: Supplies face, scalp, and neck.

• Internal Carotid Artery: Supplies brain and eyes.

Identify the branches of the external carotid artery.

• Superior thyroid artery

• Lingual artery

• Facial artery

• Occipital artery

• Posterior auricular artery

• Maxillary artery

• Superficial temporal artery.

Name the arterial structure in the neck region that contains baroreceptors.

Carotid sinus.

Identify the veins that combine to form the brachiocephalic vein.

The subclavian and internal jugular veins.

Identify the branches of the internal carotid and vertebral arteries and the branches of the internal jugular veins, and name the areas each serves.

Internal Carotid Artery:

• Branches: Ophthalmic artery, Anterior cerebral artery, Middle cerebral artery.

• Areas Served: Brain, Eyes, Forehead.

Vertebral Artery:

• Branches: Posterior inferior cerebellar artery, Anterior spinal artery.

• Areas Served: Brainstem, Cerebellum, Spinal cord.

Internal Jugular Vein:

• Branches: Facial vein, Pharyngeal vein, Superior thyroid vein.

• Areas Served: Head, Neck.

Name the three branches of the internal carotid artery.

• Anterior cerebral artery

• Middle cerebral artery

• Ophthalmic artery

Describe the structure and function of the cerebral arterial circle.

• Structure: It is a ring-like structure formed by the anterior and posterior communicating arteries along with segments of the internal carotid and vertebral arteries.

• Function: It provides collateral circulation to the brain, ensuring a constant blood supply even if one of the arteries is blocked.

Name the veins that drain the dural sinuses of the brain.

• Superior sagittal sinus: Drains into the confluence of sinuses.

• Inferior sagittal sinus: Drains into the straight sinus.

• Straight sinus

• Transverse sinuses

Identify the branches of the descending aorta and the branches of the venae cavae, and name the areas each serves.

Descending Aorta:

• Branches: Thoracic aorta, Abdominal aorta

• Areas Served: thoracic region, abdominal region

Vena Cavae:

• Branches: Superior vena cava, Inferior vena cava

• Areas Served: Upper body, lover body

Which vessel collects most of the venous blood inferior to the diagram?

The Inferior Vena Cava.

Identify the major branches of the inferior vena cava.

• Right and left common iliac veins

• Right and left internal iliac veins

• Right and left external iliac veins

Grace is in an automobile accident and her celiac trunk is ruptured. Which organs will be affected most directly by this injury?

The liver, stomach, and spleen.

Branches of the visceral arterial vessels and the venous branches of the hepatic portal system, and name the areas each serves.

Visceral Arterial Vessels:

• Branches: Celiac trunk, Superior mesenteric artery (serves small intestine, part of large intestine), Inferior mesenteric artery (serves part of large intestine).

• Areas Served: stomach, liver, pancreas/ small intestine, part of large intestine/ part of the large intestine

Venous Branches of the Hepatic Portal System:

• Branches: Splenic vein, Superior mesenteric vein, Inferior mesenteric vein

• Areas Served: drain blood from respective areas to the liver

List the unpaired branches of the abdominal aorta that supply blood to the visceral organs.

• Celiac artery: Supplies blood to the stomach, liver, and spleen.

• Superior mesenteric artery: Supplies blood to the small intestine and part of the large intestine.

• Inferior mesenteric artery: Supplies blood to the remaining part of the large intestine.

Identify the three veins that merge to form the hepatic portal vein.

• The splenic vein

• The inferior mesenteric vein

• The superior mesenteric vein

Identify two veins that carry blood away from the stomach.

• Hepatic portal vein

• Gastric vein

Describe the function of the hepatic portal system, and name its primary vessel.

• Carries blood from the digestive organs to the liver for processing.

• Primary vessel is the hepatic portal vein.

Identify the branches of the common iliac arteries and the branches of the common iliac veins, and name the areas each serves.

• Common Iliac Arteries:

  • External Iliac Artery: Serves lower limbs.

  • Internal Iliac Artery: Supplies pelvic organs and gluteal region.

• Common Iliac Veins:

  • External Iliac Vein: Drains lower limbs.

  • Internal Iliac Vein: Drains pelvic organs and gluteal region.

Name the first two branches of the common iliac artery.

• External iliac artery

• Internal iliac artery

The plantar venous arch carries blood to which three veins?

• The medial plantar vein

• The lateral plantar vein

• Deep plantar vein

A blood clot that blocks the popliteal vein would interfere with blood flow in which other veins?

The femoral, anterior and posterior tibial veins.

Describe the pathways taken by oxygenated blood and deoxygenated blood in the systemic circuit.

Oxygenated blood is pumped from the left ventricle of the heart through the aorta to the body tissues.

Deoxygenated blood returns to the right atrium via the superior and inferior vena cava.

Trace the path of a drop of blood from the left ventricle to the right hip joint.

Left ventricle—>ascending aorta—>aortic arch—>thoracic aorta—>abdominal aorta—>right common iliac—>ight external iliac—>right femoral—>right deep femoral—>right hip joint

Trace the path of a drop of blood from the right forearm to the right atrium.

Right forearm—>right brachial—>right axillary—>right subclavian—>right brachiocephalic—>superior vena cava—>right atrium

Describe the differences between fetal and adult circulation patterns.

• Fetal circulation has ductus arteriosus & foramen ovale, while adult circulation lacks these.

• Fetal circulation bypasses lungs, adult circulation includes pulmonary circulation.

• Fetal circulation receives oxygen from placenta, adult circulation from lungs.

Identify changes in blood flow patterns at birth.

Closure of the ductus venosus, foramen ovale, and ductus arteriosus.

List common congenital heart problems with a fetus.

1. Ventricular Septal Defect (VSD)

2. Atrial Septal Defect (ASD)

3. Tetralogy of Fallot

4. Transposition of the Great Arteries

5. Hypoplastic Left Heart Syndrome

Hypoplastic Left Heart Syndrome

A congenital heart defect where the left side of the heart is underdeveloped, affecting blood flow. It requires surgical intervention for treatment.