Biology Chapter 22 and 23 Review

Respiratory and Circulatory/Cardiovascular Systems

Chapter 22: Gas Exchange - Terms and Concepts to Review

Three Phases of Gas Exchange

  • Gas exchange in humans involves breathing, transport of gases, and exchange with body cells

  • Breathing

    • Inhale O2

    • Exhale CO2

    • They exchange between the alveoli and capillaries within the lungs

  • Transport of gases

    • Gases are transported by the circulatory system

  • Exchange of Gases between blood and body

    • Between cells and capillaries

    • Body cells give CO2, capillaries give O2

Respiratory Surfaces

What are they and where are they found?

  • They are made up of living cells; gas exchange occurs by diffusion across this layer of cells.

  • Idk where they are located

  • Alveoli, nasal cavity, and capillaries

  • Located in respiratory organs where gas exchange happens

What are the characteristics that hold true for all respiratory surfaces?

  • Must be moist to function

    • Diffusion will not work with a dry surface

    • Before they can diffuse they must first dissolve in the moist layer

  • A single, thin layer of cells

    • Less tissue to move past

    • Allows for quickly and easy diffusion

  • Large Surface Area

    • Maximizes diffusion

  • Gases should travel a short distance

    • Vessels are near the respiratory surfaces

    • This is so they do not need to travel far

  • Respiratory organs

    • Is a structure in which gas exchange occurs; it houses the respiratory surfaces

    • Examples: lungs, tracheal system

Respiratory System Structure and Function - make sure you can label the parts and comment on the function.

  • The respiratory system is a network of airways, lungs, and respiratory surfaces.

  • Nasal cavity (functions of nose hairs, mucus, cilia, blood vessels)

    • Smell receptors sample air, if it smells bad maybe do not eat

    • Hairs are part of innate immune system (stop bacteria and particles)

    • Mucus: catches things like pathogens and humidifies the air to make diffusion easier

    • Blood vessels around the nasal cavity warm the air to protect internal temp and make diffusion easier

    • Cilia moves mucus in your nose

  • Pharynx (throat)

    • Fork between food passage and wind pipe/trachea

  • Larynx (voice box, vocal cords), cartilage

    • Also called the voice box

    • Contains vocal cords

    • Made of cartilage

  • Trachea (windpipe), cartilage

    • Passage way between larynx and lungs

    • C shaped rings of cartilage prevent the trachea from collapsing during negative pressure (inhalation)

    • Mucus is inside the trachea to moisten the air and trap debris

    • Cilia move mucus through the wind pipe

  • Bronchi (right and left bronchus), cartilage

    • Right Bronchus and left bronchus

    • Also has cartilage for support

    • Cilia moves mucus through the bronchi

  • Bronchioles

    • Smallest air tube in the lungs

    • Dead end in microscopic air sacs (alveoli)

  • Alveoli

    • Microscopic air sacs, millions per lung

    • Contain white blood cells (leukocytes) to destroy invaders

    • The site of gas exchange is the location of respiratory surfaces

  • Surface tension, role of surfactant

    • Water covers the alveoli on the inside (moist layer)

    • The water is attracted to the water across the alveoli (they want to form H bonds)

    • If the water in the alveoli formed H bonds they would collapse the alveoli

    • Surfactant is a chemical that is released by cells in the alveoli to reduce the surface tension in the alveoli by breaking the H bonds

  • Diaphragm

    • Sheet of muscle used for breathing

    • It contracts for inhaling - moves down

    • Relaxes for exhaling - moves up

  • Pleural Membrane

    • Double layer membrane with pleural fluid in between; connects the lungs to the ribs

    • Inner membrane is the visceral pleura

    • Outer parietal pleura

  • Intercostal Muscles

    • Muscles located in between the ribs

    • It contracts for inhaling - moves up and out

    • It relaxes for exhalation - moves down and in

Explain the mechanics of breathing - describe the physical events that lead to inhalation and exhalation.

Explain negative pressure breathing

  • Contractions and relaxations of diaphragm and intercostal muscles

  • Changes in lung volume and pressure

  • Air flow from high gas concentration/pressure → low gas concentration/pressure

    • Inhalation

      • diaphragm and intercostal muscles contract (active)

      • chest cavity’s volume increases thus pressure decreases

      • Low pressure in lungs, high pressure outside

      • O2 rushes into the lungs

    • Exhalation

      • Diaphragm and intercostal muscles relax (passive)

      • Chest cavity’s volume decreases thus pressure increases

      • High pressure in the lungs, low pressure outside

      • CO2 gets pushed out of the lungs

    • Ventilation - is the movement of air or water over a respiratory surface

    • Breathing - is the ventilation of the lungs through alternating inhalation and exhalation

    • Negative Pressure is when the pressure is less than the atmospheric pressure

Explain how breathing is controlled

  • Central breathing control center (brain) - monitors changes in pH in blood and cerebrospinal fluid (CSF) due to CO2 concentration

    • Central (main) breathing center is a group of nerve cells

    • It is located in the medulla

    • The medulla indirectly detects and responds to the amount of CO2 in the blood

    • Whenz more CO2 enters the blood more hydrogen ions are produced

    • More H+ ions in the blood decreasing the ph level (more acidic) of the blood

    • The Cerebrospinal fluid’s (CSF) ph level decrease is detected by the medulla

    • Medulla sends a signal to the diaphragm and intercostal muscle to increase the rate and depth of ventilation

  • What happens when you exercise?

    • You produce more CO2 thus you need to breathe faster and heavier

  • Secondary breathing control centers (certain arteries) - monitor changes in blood O, levels (in extreme low O2 environments) and communicates with the brain

    • Peripheral Breathing Control Centers are located in blood vessels

    • Can detect CO2 levels and O2 levels when they are very low

    • They send signals to the medulla to increase breathing

  • Hyperventilation and rebreathing

    • Breathing too fast

    • Excess CO2 is expelled

    • Without CO2 the body is unable to determine if it needs to breath

    • Sometimes causes the person to pass out

    • Rebreathing traps the CO2 to breath out in a bag so you can rebreathe the CO2 and keep your CO2 levels normal

  • Electrical signals from brain → diaphragm and intercostal muscles

    • Medulla sends a signal to the diaphragm and intercostal muscle to increase the rate and depth of ventilation

O2 and CO2 transport through blood

  • O2 bound to hemoglobin, dissolved in plasma

    • Two ways O2 is transported

    • Most binds to hemoglobin (Hb - O2), O2 binds to the 4 iron groups

    • Some dissolves into the plasma

  • CO2 dissolved as bicarbonate ions, bound to hemoglobin, dissolved in plasma

    • Three ways CO2 is transported

    • Most are transported as HCO3- (CO2 + H20 -> H2C2O3 -> H+ + HC2O3-)

    • Some binds to hemoglobin

    • Some dissolves in the plasma

Path of O2 and CO, gases between respiratory system and cardiovascular system

  • identify the path of 02 molecules from the outside air, through the respiratory system to the site of gas exchange in the lungs, into the bloodstream, through the heart, and to body cells for gas exchange

  • identify the path of CO molecules from the body cells, into the bloodstream, through the body, through the heart, to the site of gas exchange in the lungs, through the respiratory system, and to the outside air

  • Connect O2 and COz to cellular respiration

Chapter 23: Circulatory (Cardiovascular) System - Terms and Concepts to Review

Components of the Circulatory System

  • Also called the cardiovascular system

  • Closed circulatory system

    • Blood, hearts, vessels

      • Blood Vessels

        • Tubular structures that transport blood throughout the body

        • Defined by the direction of blood flow

      • Arteries carry blood away from the heart

      • Veins carry blood to the heart

      • Capillaries carry blood from small arteries to small veins

  • Double circulation

    • Pulmonary circuit, Systemic circuit, Coronary circuit

      • Pulmonary circuit is between lungs and heart

      • Systemic circuit is between heart and body

      • Coronary Circuit is between the chambers of the heart and the cells of the heart

Human circulatory system

  • Cardiac muscle of the heart is involuntary

  • Four chambers of the heart

    • 2 atria: uppermost chambers (superior)

    • 2 ventricles: inferior chambers

  • Four major valves in the heart (know 2 names for each)

    • Ensure unidirectional flow of blood

    • L AV (bicuspid, mitral)

    • R AV (tricuspid)

    • L SL (aortic)

    • R SL (pulmonary)

    • Mitral valve prolapse (mitral valve becomes flappy causing backflow)

    • Heart murmur (sound in the heart that is a sign of disease)

  • Major arteries and veins in both the pulmonary and systemic circuit

    • Arteries: aorta, pulmonary arteries

    • Veins: vena cava, pulmonary vein

  • Role and location of capillaries in the lungs and the upper and lower parts of the body

    • Capillaries exchange gases

    • O2 from lungs to capillaries, CO2 from body cells to capillaries

Cardiac Cycle

  • Refers to physical events in` the heart so use terms like contraction and relaxation to describe the events

    • Diastole: the period of relaxation (chambers fill up to 80%)

      • AV valves open

      • SL valves closed

    • Atrial systole: contraction of atria (push blood to ventricles)

      • AV valves open

      • SL valves closed

    • Ventricular systole: contraction of ventricles (push blood out of heart)

      • AV valves closed

      • SL valves forced open

  • Left side has thicker cardiac muscle because pumping to whole body

  • Heart sounds

    • Closing of AV valves during ventricular systole

    • Closing of SL valves during diastole

Electrical activity in the heart (monitored with an ECG)

  • Refers to electrical events in the heart so use terms like polarized, depolarized, and repolarized to describe the events

    • Electrical signals cause muscles to contract

    • Absence of signals causes them to relax

    • Polarized cell has a net negative charge inside the cell and net positive outside

      • Polarized means at rest

    • Depolarized cell has a positive charge inside the cell and negative outside

      • Depolarized means transmitting an electrical signal

    • Repolarized cell is back at rest

  • Electrical signals originate at the SA node (pacemaker)

    • Delayed at the AV node and spread through the atria

    • Specialized muscle fibers pass signals to the heart apex

    • Signals spread throughout the ventricles

  • P wave, QRS wave, T wave

    • P wave: depolarization of the atria (causes atrial systole)

    • QRS wave: depolarization of the ventricles (causes ventricular systole)

      • Also repolarization of the atria is hidden during this wave

    • T wave: repolarization of the ventricles (begins diastole)

  • ECG = electrocardiogram

  • BP = systolic pressure/diastolic pressure

Atherosclerosis

  • Cause of Heart attack

    • Buildup of plaque in arteries

Arteries, capillaries, and veins

  • Structure and function of each – similarities and differences

  • Artery

    • Epithelium: thin, smooth layer to reduce friction

    • Smooth muscle: involuntary thick layer

      • Relaxation: vasodilation

      • Contraction: vasoconstriction

      • Lots of pressure

    • Connective tissue: thick layer, fibers for strength and elasticity

      • Lots of pressure

  • Vein

    • Epithelium: thin, smooth layer to reduce friction

      • Contains one-way valves

    • Smooth muscle: involuntary thick layer (contracts to move blood)

    • Connective tissue: thin layer since less pressure

      • Fibers prevent vein collapse

  • Capillaries

    • Connective tissue: none

    • Smooth muscle: none

    • Epithelium: thin, smooth layer (single layer of cells)

      • Site of gas diffusion

  • Structure determines function

  • Aorta → arteries → arterioles → capillaries → venules → veins → vena cavae

Diffusion of gases occurs through capillaries

  • High concentration/pressure → low concentration/pressure

  • Characteristics of capillaries that make them ideal for diffusion

    • Surface area, thin walls, small diameter so diffused substances travel short distances, low velocity

Blood Pressure

  • Systolic pressure, diastolic pressure

  • Meaning of a blood pressure numbers, such as 120/70

  • Sphygmomanometer: used to measure blood pressure

  • Major trends in blood pressure and blood velocity throughout the blood vessels and why these trends make sense

    • Blood pressure decreases as blood moves away from the aorta

      • Increasing number of branching vessels

    • Blood velocity decreases as blood moves away from the heart

      • More area to flow through

      • Less pressure

      • Resistance/friction

  • Aorta → arteries → arterioles → capillaries → venules → veins → vena cavae

  • High blood pressure (hypertension)

  • Movement of blood through veins

    • Contraction of skeletal muscles

Contents of blood

  • 55% plasma

    • Water

    • Ions (bicarbonate)

    • Proteins: antibodies

    • O2 and CO2

  • 45% cells

    • WBC (leukocytes) for defense and immunity

    • Platelets (cell fragments) for blood clotting

    • RBC (erythrocytes) for transport of O2 and CO2

  • Functions of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets

  • Anemia, hemoglobin (iron)

  • Blood clotting

    • Plug leaks when blood vessels are injured

    • Platelets adhere to the exposed connective tissue

    • Platelet plug forms

    • A fibrin clot forms

      • Inactive fibrinogen activates to fibrin (sticky protein strands)

      • Activated by an enzyme

Blood cell formation

  • Stem cells in red bone marrow

  • Spongy bone of long bones