Bio 110 Lec Chapter 42 Circulation

Front 1

Open circulatory system

Back 1

- hemolymph bathes internal organs directly while moving through sinuses

- circulation results from contractions of heart (dorsal vessel) and body movements

- insects, arthropods, mollusks

Front 2

Hemolymph

Back 2

- body fluid which acts as blood and interstitial fluid

Front 3

Sinuses

Back 3

- where chemical exchange ebtween hemolymph and cells occurs

- interconnected system of spaces surrounding organs

Front 4

Closed circulatory system

Back 4

- circulatory system in which blood is confined to the vessels + distinct interstitial fluid

- heart/s pump blood into large vessels, which branch out

- materials are exchanged between blood and interstitial fluid in organs

- annelids, squids, octopuses, vertebrates

Front 5

Cardiovascular system

Back 5

- heart, blood vessels, and blood

Front 6

Atrium

Back 6

- 1-2

- thin-walled chambers that receive blood

- fish: 1A1V, ventricle -> gill capillaries (get O2, CO2 out) -> arteries -> capillary beds in other organs (systemic capillaries) -> veins -> atrium, all aided by swimming motions

- amphibians: 2A1V: ventricle -> lungs and skin -> LA -> V -> organs -> RA, passes througn V twice to ensure sufficient BP, ridge in ventricle diverts most blood

- reptiles (not crocs): 2A1V, partially divided V

- birds, mammals: 2A2V

Front 7

Ventricles

Back 7

- 1-2

- thick-walled chambers that pump blood out

Front 8

Arteries

Back 8

- carry blood Away from heart to organs

- thicker walls to wihstand force when heart pumps blood

Front 9

Arterioles

Back 9

- branched arteries that give rise to capillaries

- contraction and relaxation regulates blood flow to capillary bed

Front 10

Capillaries

Back 10

- site of chemical exchange between blood and interstitial fluid

- have thin, porous walls

- arranged into capillary beds

- walls made of single, leaky layer of flattened endothelial cells that overlap at edges

- materials cross in vesicles, diffusion, and blood flow

- most fluid reenters blood as interstitial fluid, others return to blood via lyymphatic system

Front 11

Capillary bed

Back 11

- networks of capillaries that infiltrate each tissue

- total diameter is much greater than in artery -> in accordance w/ law of continuity, blood flow slows

- has precapillary sphincters, rings of smooth muscle at entrance that contract/relax to regulate blood flow

Front 12

Venules

Back 12

- rejoined capillaries

- converge to form veins

Front 13

Veins

Back 13

- carry blood Vack to heart along with breathing

- in breathing, pressure change in thorracic cavity cause veins to fill

Front 14

Systemic and pulmocutaneous circuit

Back 14

- pulmocutaneous: blood flow to lungs and skin

- systemic: blood flow to all other organs

-

Front 15

Double circulation

Back 15

- scheme of separate pulmonary and systemic circuits

Front 16

Pulmonary circuit

Back 16

- deoxygenated blood -> lungs -> oxygenated -> heart

Front 17

Atrioventricular valve

Back 17

- found between each atrium and ventricle

- prevent blood from flowing back during ventricular contraction

- RA/V: tricuspid; LA/V: mitral

- heart murmur: backflow in one/more valves

Front 18

Semilunar valves

Back 18

- located where aorta leaves LV and pulmonary artery leaves RV

- aortic and pulmonary valve

- prevent blood backflow to ventricles when it relaxes

Front 19

Pulse

Back 19

- sensation from rhythmic stretching of arteries caused by increased Bp during systole

Front 20

Heart rate

Back 20

- number of heartbeats per minute

- average: 60-70

- inverse relationship w/ body size; some shrews: 600 bpm

Front 21

Cardiac cycle

Back 21

- complete sequence of contraction and relaxation

Front 22

Systole

Back 22

- when heart muscle contracts and chambers pump blood

Front 23

Hemocyanin

Back 23

- O2-carrying pigment in arthropods and mollusks

- binding is copper -> blue color

- dissolved directly in plasma, not confined to cells

Front 24

Diastole

Back 24

- when heart muscles relax and chambers fill w/ blood

Front 25

Cardiac output

Back 25

- volume of blood LV pumps out into systemic circuit per minute

- depends on heart rate and stroke volume

- average: 5.25L /min

Front 26

Stroke volume

Back 26

- amount of blood pumped by LV each time it contracts

- average: 75 mL per beat

Front 27

Sinoatrial (SA) node

Back 27

- controls tempo of contraction

- in RA wall, near entrance of superior vena cava

- composed of specialized muscle tissue w/ characteristics of both muscle and nerve tissue

- when it contracts, it initiates an excitation wave -> spreads rapidly and causes atria to contract -> blood flow to ventricles

Front 28

Pacemaker

Back 28

- sinoatrial node

Front 29

Atrioventricular (AV) node

Back 29

- specialized mucle tissue

- near base of wall separatiing atria

- delays impulse for 0.1 seconds to ensure atria are empty -> ventricles pump blood out

Front 30

Electrocardiogram

Back 30

- detects electrical currents caused by impulses

- uses electrodes placed on skin

Front 31

Endothelium

Back 31

- inner layerof walls of arteries and veins (after elastic connective tissue for stretching and recoil, then smooth muscle and elastic fibers)

- simple squamous epithelium

Front 32

Blood pressure

Back 32

- hydrostatic force that blood exerts against vessel wall

- BP of arteries>V, especially during ventricular contraction

Front 33

Peripheral resistance

Back 33

- when blood enters arteries faster than it can leave

- caused by arteriole impedance

- drives blood into capillaries constantly

- stress -> neural and hormonal responses -> smooth muscles contract, increasing resistance

Front 34

Lymphatic system

Back 34

- system that recovers lost fluid and proteins and returns it to blood

- drains into circulatory system at two locations near shoulders

Front 35

Lymph

Back 35

- similar in composition to interstitial fluid

- diffuses into lymph capillaries, which intermingle with blood capillaries

- lymph capillaries also absorb fats -> transports to circulatory system

Front 36

Lymph nodes

Back 36

- specialized swellings along system that filter lymph and attack virus and bacteria

- have specialized lymph blood cells

- lymph node WBCs rapidly multiply during infection

Front 37

Plasma

Back 37

- liquid matrix that suspends different blood cell types

- 90% water, which contains electrolytes and plasma proteins

- electrolytes: inorganic salts in the form of dissolved ions, help maintain osmotic balance and buffer blood

- plasma contributes to blood viscosity

- contains fibrinogens: clotting factors, if no clotting factors, is called serum

Front 38

Erythrocytes

Back 38

- red blood cells

- biconcave discs that function in oxygen transport

- lack nuclei and mitochondria

- generate ATP through anaerobic metabolism

- contain hemoglobin

- circulates in blood for 3-4 months before being destroyed by phagocytic cells in liver and spleen

- CO2 diffuses in, blood -> diffuses to spinal cord -> reacts with water to form bicarbonate -> bicarbonate -> bicarbonate diffuses into plasma -> lowers pH -> depth and rate of breathing increases

Front 39

Hemoglobin

Back 39

- iron-containing protein in RBCs that reversibly binds oxygen

- Bohr shift: lowers affinity for oxygen due to drop in pH -> shifts dissociation curve right

Front 40

Leuokcytes

Back 40

- white blood cells

- function in defense and immune

- five main types: basophils, eosinophils, neutrophils, lymphocytes, monocytes

- most time spent in interstitial fluid and lymphatic system

- become specialized during an infection and produce immune response

Front 41

Platelets

Back 41

- originate as pinched-off cytoplasmic fragments of large bone marrow cells

- lack nuclei

- function in blood clotting

Front 42

Pluripotent stem cells

Back 42

- found in red marrow of bones

- give rise to cellular elements

- new number of blood cells produced = number of dying cells

Front 43

Dissociation curve

Back 43

- cooperative nature of heme groups

- binding of O2 to one subunit: shape change that increases affinity of other three subunots

- unloading of oxygen from one heme group: conformational change that stimulates unloading in other three

- Bohr shift: lowering of hemoglobin's affinity for oxygen upon a drop in pH

Front 44

Erythropoietin

Back 44

- hormone that stimulates production of erythrocytes in bone marrow

- converted by kidneys from plasma protein when tissues are not receiving enough oxygen

Front 45

Fibrinogen

Back 45

- blood plasma protein produced in liver

- converted to fibrin through thrombin

Front 46

Fibrin

Back 46

clotting factors form an exymatic cascade that converts plasma protein prothrombin into thrombin

- clotting factors form an exymatic cascade that converts plasma protein prothrombin into thrombin -> thrombin catalyzes change of fibrinogen (ciurculates in blood) -> fibrin

- thrombin catalyzes change of fibrinogen (ciurculates in blood) -> fibrin

- aggregates into threads that form the clot

Front 47

Hemophilia

Back 47

- inherited defects in clot formation

- excessive bleeding from minor injuries

Front 48

Thrombus

Back 48

- spontaneous clots formed from platelets and coagulated fibrin

- blocks key blood vessels; if coronary arteries -> heart attack; if brain -> stroke

- more likely in individuals with cardiovascular disease

Front 49

Cardiovascular disease

Back 49

- diseases o heart and blood verssels

Front 50

Heart attack

Back 50

- death of cardiac muscle from prolonged blockage of one/more coronary arteries

Front 51

Stroke

Back 51

- death of nervous tissue from blockage of brain arteries

Front 52

Atherosclerosis

Back 52

- plaques developing on inner walls of arteries

- increases risk of clot formation and heart attack

Front 53

Arteriosclerosis

Back 53

- form otherosclerosis

- plaques hardened by calcium deposits

Front 54

Hypertension

Back 54

- high BP

- may promote atherosclerosis

- increases risk of heart attack and stroke

Front 55

Low-density lipoproteins (LDLs)

Back 55

- low conc. in blood correlate with atherosclerosis

- ratio to HDL increased by smoking

Front 56

High-density lipoproteins (HDLs)

Back 56

- may reduce cholesterol depositionin arterial plaques

- conc. increased by exercise

Front 57

Gas exchange

Back 57

- movement of O2 and CO2 between animal and environment

- suppliessss O2 and removes CO2, supporting cellular respiration

Front 58

Respiratory medium

Back 58

- source of oxygen

- air for terrestrial animals (21% oxygen), water for aquatic animals (dissolved oxygen content varies due to temperature, solute conc, and other factors

Front 59

Respiratory surface

Back 59

- portion of animal surface where gas exchange with respiratory medium occurs

- O2 in, CO2 out -> must first be dissolved in water coating respiratory surface

- must be large enough for entire body

(1) protozoa, unicellular organisms: entire surface area

(2) cnidarians, sponges, flatworms: plasma membrane contacts outside enviornment

(3) long, thin, some ambhibians: skin

Front 60

Gills

Back 60

- outfoldings in most aquatic animals in direct contact with water

- some invertebrates (e.g. echinoderms): simple shapes, distributed over entire body

- other invertebrates (e.g. annelids): flap-like, extend frome each body segment, or clustered at one end and long and feathery

- mollusks, fishes: localized on a body region, finely subdivided fo higher surface area

Front 61

Ventilation

Back 61

- method for increasing flow of respiratory medium over respiratory surface

- brings in fresh O2 and removes CO2

- low O2 conc in water -> fish must expend a large amount of energy to ventilate

Front 62

Countercurrent exchange

Back 62

- when blood flows opposite to direction where water passes over gills, maintaining a constand conc gradient

Front 63

Myoglobin

Back 63

- respiratory pigment similar to hemoglobin

- comprised of dsingle subunit and one heme unit

- hgher concentration in muscles of Weddell seals, allowing them to store 25% of oxygen in muscles

Front 64

Tracheal system

Back 64

- made up of tiny air tubes that branch throughout body

- enters hrough spiracles, diffuses to small branches which extend to cell surfaces

Front 65

Lungs

Back 65

- highly vascularized invaginations restricted to one location

- occur in various stages in terrestrial vertebrates: internal mantle in land snails, booklungs in spiders

- in mammals: hihgly subdivided, large SA

- in frogs: simple, balloonlike, limited SA

Front 66

Vocal cords

Back 66

- function as voice box

- located in larynz

Front 67

Larynx

Back 67

- A4

- nostrils -> pharynx -> gllottis -> larynx

Front 68

Trachea

Back 68

- A5

- after larynx

Front 69

Bronchi

Back 69

- A6

- forks of trachea

Front 70

Bronchioles

Back 70

- A7

- branched bronchi

Front 71

Alveoli

Back 71

- A8

- lined with epithelium which serves as repiratory surface

- O2 dissolves in moist film coverin epithelium -> diffuses across to capillaries covering each alveolus -> CO2 moves in opposite direction by diffusion

Front 72

Breathing

Back 72

- alternate inhalation and exhalation of air

- used by vertebrates to ventilate lungs

Front 73

Positive pressure breathing

Back 73

- used by frogs to ventilate lungs

- air pulled into oral cavity by lowering floor region -> exhaled by lung compression

Front 74

Negative pressure breathing

Back 74

- used by mammals to ventilate lungs

- inhalation causes thoracic cacvity to enlarge

- rib muscles/diaphragm contract, expanding rib cage -> surface tension of fluid causing lungs to follow -> lung volume increases

Front 75

Diahragm

Back 75

- dome-shaped, thin sheet of mucles which forms bhottom wall of thoracic cavity

Front 76

Tidal volume

Back 76

- volume of air inhaled or exhaled during normal quiet breathing

- ~500 mL in humans

Front 77

Vital capacity

Back 77

- maximum air volume that can be inhaled or exhaled during forced breathing

- 3400/4800mL in college-age females/males

Front 78

Residual volume

Back 78

- amount of air that still remains in lungs after forced ventilation

Front 79

Parabronchi

Back 79

- tiny channels in bird lungs that keep air flowing in one direction regardless if inhaling and exhaling

- provides constant supply of oxygen

Front 80

Breathing control centers

Back 80

- nerves in medulla oblongata and pons that send impulses to rib muscles or diaphragm, stimulating muscles to contract

- increases breathing rate when detected O2 levels are low

Front 81

Partial pressure

Back 81

- determines dffusion rate

- proportional to total atmospheric pressure, PO2: 160 mm Hg, PCO2: 0.23 mm Hg

- always high -> low

- E.g. blood arriving from lungs: lower PO2 ad hhigher PCO2, so exhchanges CO2

Front 82

Respiratory pigments

Back 82

- proteins containing metal atoms which carry oxygen

- metal atoms responsible for color