Exam 3 quizlet notes

Function of Cardiovascular System

  • Transport system for hormones, oxygen, nutrients, waste, etc.

    • Carries the good stuff to the tissues.

    • Removes the bad stuff from the tissues.

Main Components of Cardiovascular System

  • Heart

    • Function: acts as a pump.

    • Size: approximately the size of your fist.

    • Blood Output:

    • At rest: approx 5 L/min (~1 gallon).

    • During maximal exercise: approx 20-25 L/min (4-5 gallons).

  • Blood Vessels

    • Analogy: think of them as highways for blood.

  • Blood

    • Analogy: think of it as the vehicle on the highways.

Heart Structure and Function

  • Number of pumps: 2 separate pumps.

    • Right side: pulmonary circuit.

    • Function: gets blood through the lungs to pick up O2.

    • Left side: systemic circuit.

    • Function: gets blood through the rest of the body to drop off O2.

  • Each pump contains:

    • Atrial chamber: top chamber, small and weaker.

    • Ventricular chamber: bottom chamber, thick and muscular, pumps blood.

  • Left Ventricle: especially thick and muscular due to its role in pumping blood against gravity all the way down to toes and back up.

  • Pressure Gradient:

    • Heart creates a one-way pressure gradient necessary for blood flow.

    • High pressure when blood leaves the heart.

    • Low pressure when blood returns to the heart.

Blood Vessels

  • Composition:

    • Arteries: take blood away from the heart.

    • Veins: take blood to the heart.

    • Capillaries: sites of exchange for nutrients, gases, hormones.

  • Fun Fact: Approx 70,000 miles of blood vessels in the body are enough to circle the Earth 3 times.

  • Oxygen Content:

    • Generally, arteries contain more O2 than veins.

Blood Composition and Functions

  • Typical adult has approx 5 L of blood.

  • Functions:

    • Transports O2 and nutrients to tissues.

    • Carries CO2 and other waste products away from tissues.

  • Blood Composition:

    • Composed of plasma and formed elements (RBCs, WBCs).

Cardiac Cycle

  • Systole: time the heart/ventricle is contracting.

  • Diastole: time the heart/ventricle is relaxing.

  • Cardiac Cycle: the total time it takes for the heart to go through systole and diastole.

Plasma

  • Composition:

    • Primarily made up of water (92%), proteins (7%), and solutes (like ions Na+ and K+).

  • Functions of Plasma Proteins:

    • Albumin:

    • Function: maintains colloid osmotic/oncotic pressure, helps hold onto fluid in the bloodstream, especially during passage through capillaries.

    • Source: liver.

    • Without it, can lead to edema (fluid in unwanted locations).

    • Globulin:

    • Function: clotting factors.

    • Source: liver and lymphoid tissue.

    • Fibrinogen:

    • Function: forms fibrin threads for clotting (mesh network to hold platelets).

    • Source: liver.

    • Transferrin:

    • Function: transports iron.

    • Source: liver and other tissues.

Formed Elements of Blood

  • Erythrocytes (Red Blood Cells):

    • Description: bi-concave disks that carry O2.

  • Leukocytes (White Blood Cells):

    • Description: irregularly shaped cells that fight infections.

  • Platelets:

    • Description: round or oval shapes that facilitate clotting.

Types of Leukocytes

  • Granular leukocytes:

    • Contain prominent granules assisting specific WBC functions:

    • Basophils (< 1%): release histamine, initiate inflammatory responses & allergic reactions.

    • Eosinophils (1-3%): release chemicals that cross cell membranes, deal with allergic reactions and fight parasitic infections.

    • Neutrophils (60-70%): first responders to infection, phagocytize bacteria.

  • Agranular leukocytes:

    • Do not contain prominent granules.

    • Lymphocytes (20-30%): produce B and T cells, with B cells producing antibodies.

    • Monocytes (1-6%): differentiate into macrophages that phagocytize pathogens and cellular debris.

Hemoglobin

  • Definition: iron compound found on RBCs.

  • Structure: made up of 4 folded proteins.

  • Function: primarily binds to oxygen, also binds to carbon monoxide, H+ ions, and carbon dioxide.

  • Breakdown: hemoglobin can be broken down into iron and non-iron globin.

Hematocrit

  • Definition: proportion of blood made up of RBCs.

  • Formula: extHematocrit=racextVolumeofRBCsextTotalBloodVolumeext{Hematocrit} = rac{ ext{Volume of RBCs}}{ ext{Total Blood Volume}}

  • Typical Ranges:

    • Females: 37-47%.

    • Males: 42-52%.

    • Note: females have lower hematocrit due to the menstrual cycle.

Blood Composition Overview

  • Components in a Test Tube:

    • Plasma: on top (water, proteins, nutrients, hormones).

    • Buffy Coat: middle (WBCs and platelets).

    • Hematocrit: bottom (RBCs).

  • Main Component of Plasma: Water (92%).

Heart Action Potential and Cardiac Function

  • Pacemaker Cells:

    • Found in the heart, facilitate the heart's pumping function and set heart rate.

    • Also known as autorhythmic cells.

  • Differences from Skeletal Muscle:

    • No resting potential.

    • Release of action potentials that can occur spontaneously.

  • Action Potential Phases of Pacemaker Cells:

    • Drift (Sodium influx): slow influx allowing for spontaneous action potentials.

    • Depolarization (calcium influx): sodium channels close, voltage-gated calcium channels open for rapid influx.

    • Repolarization (potassium efflux): occurs due to opening of voltage-gated potassium channels.

  • Importance of Drift: Allows pacemaker cells to have spontaneous action potentials, essential for heart functioning without CNS signals.

Chronotropic Agents and Heart Rate

  • Effect of Acetylcholine: Slows heart rate by opening potassium channels during drift.

  • Effect of Norepinephrine: Increases heart rate by opening sodium channels during drift, positive chronotropic effect.

  • Definitions:

    • Chronotropic: refers to heart rate.

    • Positive Chronotropic Agents: (e.g., norepinephrine) increase HR.

    • Negative Chronotropic Agents: (e.g., acetylcholine) decrease HR.

Cardiac Volume Metrics

  • End-Diastolic Volume (EDV): amount of blood in heart before contraction.

  • End-Systolic Volume (ESV): amount of blood left in the ventricle at the end of emptying/contraction.

  • Stroke Volume (SV): amount of blood pumped out of the ventricle during a single systole/contraction.

    • Formula: extSV=extEDV−extESVext{SV} = ext{EDV} - ext{ESV}

Cardiovascular Responses

  • Preload: amount of stretch during diastole, directly proportional to EDV.

  • Inotropy: force of contraction at a given preload, increased by positive inotropic agents (e.g., sympathetic nervous system, changes in ion concentrations, drugs).

  • Norepinephrine’s Role: enhances cardiac muscle contractions by increasing calcium influx during action potentials, leading to stronger contractions and increased stroke volume.

Cardiac Cycles & Sounds

  • Cardiac Cycle Phases:

    • Isovolumetric contraction

    • Ejection

    • Isovolumetric relaxation

    • Filling

  • Heart Sounds:

    • Lub: occurs at the end of filling when AV valves close.

    • Dub: occurs at the end of ejection when SL valves close.

Important Cardiovascular Measurements

  • Blood Pressure Measurement:

    • Typically referring to artery pressure.

    • Systolic Blood Pressure: occurs during contraction of the ventricles, causing arteries to expand.

    • Diastolic Blood Pressure: occurs during relaxation of the ventricles due to elastic recoil of arteries, maintaining blood flow.

  • True/False: The right and left ventricle pump about the same amount of blood: True (although pressure may differ).

Summary

  • Overall Function of the Cardiovascular System: Essential for transportation of vital elements, regulation of body conditions, and maintaining homeostasis through structured cooperation between heart, vessels, and blood components.