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Ch 23

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Terms in this set (84)

  • Circulatory system

    Facilitates exchange with all body systems by assisting diffusion

  • Cells of an organism must: (3)

    Receive nutrients

    Exchange gases

    Remove wastes

  • Capillaries

    Microscopic blood vessels, the width of one blood cell

    Formed by a single layer of epithelial cells

    Specialized for chemical exchange

    Used to increase surface area to diffuse gas and fluid with interstitial fluid

  • Gastrovascular cavity

    In simple organisms,

    Digests and distributes substances

    Sufficient for simple diffusion

    Maximizes surface area to volume ratio

  • True circulatory system: (3)

    Muscular pump (heart)

    Set of tubes to carry fluid (blood vessels)

    Circulatory fluid (blood)

  • Open circulatory system

    Fluid is not always confined within vessels

  • Hemolypmh

    Bathes internal organs/tissues directly in open systems instead of blood, hemolymph = interstitial fluid

  • Heart pumps hemolymph to tissues

    Hemolymph returns to heart via pores

  • Closed circulatory system

    Blood is confined within blood vessels

  • Order of closed system:

    Heart pumps blood through arteries

    Capillaries

    Veins return blood to heart

    Capillaries

    Oxygenated in lungs

    Repeat

  • Advantages of a closed circulatory system: (4)

    Blood flows faster

    Can selectively direct blood to specific tissues

    Large molecules/elements needed for hormone/nutrient transport can remain in the vessels for easier access

    Can support higher levels of metabolic activity

  • Blood

    The only liquid tissue, consists of cells suspended in plasma

  • Plasma make up

    90% water

    Ions, proteins, and nutrients

  • Stem cells

    Unspecialized cells that differentiate into blood cells as needed

  • Hematopoietic stem cells

    In red blood cells

  • Erythropoietin hormone

    Stimulates RBC production

  • Erythrocytes (RBC) (4)

    Transport O2

    Transport CO2

    Lack nuclei and mitochondria, therefor do not consume blood’s oxygen

    ~100 day life span

  • Leukocyte (WBC)

    Used for defence and immunity

    Much less abundant than RBC

  • Blood clotting

    A vital survival response of blocking leaks in injured vessels

  • Clotting factors

    Always present in the blood

    Platelets

    Fibrin

  • Platelets

    Cell fragments that temporarily plug injury site

  • Fibrin

    A threadlike protein that traps RBC and platelets to form a clot

  • Clotting cascade - damaged blood vessels:

    Prothrombin becomes thrombin

  • Clotting cascade - platelet plug formation:

    Fibrinogen becomes fibrin

  • Clotting cascade - clot development:

    Fibrin traps RBC and platelets to form a clot

  • Veins

    Carry O2 poor blood TOWARD the heart

  • Arteries

    Carry O2 rich blood AWAY FROM the heart

  • 3 layers of tissue in arteries and veins:

    Endothelium

    Smooth muscle

    Connective tissues

  • Endothelium

    A single layer of epithelial cells that line the vessel

  • Smooth muscle

    Regulates blood flow and pressure by constriction

  • Connective tissue

    Allows stretching

  • Valves

    Prevent the backflow of blood, keeping flow in one direction

  • Why veins have valves

    Smaller in diameter than arteries and therefor have more flow resistance/less pressure

  • Blood velocity

    Related to vessel diameter

    Large diameter = less resistance, higher volocity

    Smaller diameter = more resistance, lower velocity

  • Blood pressure

    The force blood exerts on the blood vessel walls as it is pumped through

  • Blood pressure is highest

    In arteries/closest to the heart

    Lowers as it moves further from the heart

  • Systolic pressure

    Caused by the contraction of the vessicles

  • Diastolic pressure

    The low pressure between contractions

  • Regulating high blood pressure (4)

    High bp is detected by receptors in arterial walls

    Medulla oblongata sends signals to effectors

    Cardiac cycle slows and blood volume decreases to lower cardiac output

    Smooth muscles relax to decrease resistance

  • Hypertension

    BP is chronically at or above 140/90

  • How hypertension leads to heart attack, stroke etc

    Heart has to work harder and weakens over time

    Tiny ruptures in vessels increases plaque formation

    Risk of clot formation increases

  • Precapillary sphincters

    Open and close to increase or decrease blood flow to particular regions

  • Pericardium

    A double-walled fibrous sac surrounding the heart

  • Pericardium functions

    Protection

    Anchoring

    Prevents overfilling

  • Atria

    Collection chambers for blood RETURNING to the heart, pump blood into ventricles

  • Ventricles

    Have thick, muscular walls used to pump blood across the distance of the body

  • Right ventricle

    Blood pumps to lungs

  • Left ventricle

    Blood pumps to the rest of the body, therefore thicker and stronger than the right

  • Valves

    Flaps of connective tissue that ensure blood flows in only one direction

  • Atrioventricular valves

    Between the atria and ventricles

  • Tricuspid valve

    Right AV valve

  • Bicuspid valve

    Left AV valve

  • Semilunar valves

    In arteries leaving the heart

  • Pulmonary valve

    Right semi valve (pulmonary - pulls into heart)

  • Aortic valve

    Left semi valve (aorta - artery - leaving)

  • Cardiac cycle

    The repeated contracting and relaxing of blood pumping

  • Diastole

    Heart relaxes, blood fills 4 chambers (dump)

  • Systole

    Atria contracts, ventricles fill

    Ventricles contract, blood pumps out (lubb)

  • Stethoscope

    Used to detect heart sounds

  • Heart murmur

    An abnormal heart sound that can indicate a valve disorder

  • Heart rate

    Beats per minute

  • Pulse

    Rhythmic stretching of arteries as blood is expelled from ventricles

  • Stroke volume

    Volume of blood ejected by the ventricle during contractions

  • Cardiac output

    Volume of blood per minute pumped by ventricles

  • SA node

    (Sinoatrial)

    Cardiac pacemaker cells generate electrical signals in atria to set rate of heart contractions

  • AV node

    Cardiac pacemaker cells receive and delay signals from the SA and relays to ventricles via AV bundle and Perkijne fibres

  • Steps of pacemaker signals

    Signals from SA spread through atria

    Signals delayed at AV

    Specialized muscle fibres pass signals to (bottom) heart apex

    Signals spread throughout ventricles

  • Medulla oblongata

    Cardiac control centre

  • Sympathetic nervous system

    Sends nerve impulses to increase heart rate and force of contractions

  • Parasympathetic nervous system

    Sends nerve signals to decrease heart rate

  • Adrenaline

    Released to increase heart rate

  • Arrhythmia

    A problem with heart beat rhythm caused by abnormal contractions

  • Systemic circulation

    Circulation through the whole body

  • Pulmonary circulation

    Responsible for gas exchange in humans

    NOT bronchial circulation (breathing)

  • Coronary circulation

    Circulation of blood that supplies the heart muscle

  • Coronary arteries

    Delivers nutrient rich blood to the heart

  • Coronary veins

    Remove waste from the heart

  • Heart attack

    Mycardial infarction

    Occurs when a coronary artery is blocked

  • Interstitial fluid

    Where the exchange of materials between blood and body cells occurs

  • Homeostasis

    The tendency of a cell or organism to regulate its internal conditions in order to maintain healthy and functional

    Regulated by nervous and endocrine systems

  • Negative feedback

    A change initiates a response that opposes the initial change as a control mechanism of homeostasis

    Prevents small changes from becoming too large

  • Insulin

    Decreases blood glucose

  • Glucagon

    Increases blood glucose

  • Homeostatic imbalances

    Can lead to disease and death