Respiration and Circulation

Question 1

Bulk Flow

Answer 1

• Physical movement of a medium and the molecules it contains
• all Eukaryotes require o2 for ATP
• prokaryotes exchange compounds via diffusion for gas exchange
• Done through Ventilation (movement of medium over a respiratory surface (lung/gill)
• Don through circulation (movement of fluids containing gas (pumps)

Question 2

Application of Bulk Flow

Answer 2

Ventilation
- breathing moves air containing O2 into lungs, air with CO2 is moved out
- O2 diffuses across lungs into blood, CO2 diffuses from blood into lungs
Circulation
- O2 and CO2 transported by circulatory system to and from cells
- O2 diffuses from blood into cells, CO2 diffuses out of cells into blood

Question 3

ventilation can be Active or Passive

Answer 3

• Goal is to reduce the formation of a static boundary layer
  Active:
• Animal creates ventilatory currents that flow across gas exchange surface
• uses suction or positive pressure
• expands metabolic energy
  Passive:
• Environmental air or water currents induce flow to and from the gas exchange membrane
• no use of metabolic energy

Question 4

Aquatic Animals

Answer 4

• External (tubeworms, aquatic lizards) or internal (fish) gills
• Bony fish pump water across gills, others ventilate by swimming

Question 5

Unidirectional respiration

Answer 5

• Gills protected by operculum behind the mouth cavity
• Water flows through the gill arch made up of gill filaments
• Lamellae on each side increases surface area
• Blood flow into gill is low in O2, as it loops around the gill arch it becomes oxygenated becoming rich in O2 as blood leaves the gill

Question 6

Countercurrent exchange

Answer 6

• Fluid moving in parallel directions cancel out each other (cold and hot heat and cool each other)
• Each fluid becomes as hot or cold as the other, fully transferring heat
• used to explain countercurrent oxygen flow in fish

Question 7

Land Animals

Answer 7

• Can achieve higher O2 uptake rates
• Air O2 is concentrated high, diffuses faster and is less dense than water O2
• Most use tidal ventilation:
• Increase lung volume by expanding thoracic cavity to draw in O2 rich air and expel O2 low air using passive elastic recoil

Question 8

Alveoli

Answer 8

• Where gas exchange occurs
• Sacs are blind ended never fully emptied, lungs contain stale air
• 12% of air is fresh a t the end of resting inhalation
• Surfactant reduces surface tension, allowing for easier inflation of lungs
• Surrounded by network of capillaries

Question 9

Birds

Answer 9

• Use unidirectional ventilation and cross-current flow
• First inhalation draw O2 rich air into posterior air sacs
• First exhalation moves fresh air into lung
• Second inhalation moves stale air from lung into anterior air sacs
• Second exhalation moves air out of the anterior air sacs into the trachea
• Air sacs are not needed for gas exchange, only storage

Question 10

Stimuli and Sensors

Answer 10

• Chemoreceptors detect CO2 and H+
• Carotid and Aortic bodies detect O2 and H+
• If CO2 is too high, chemoreceptors stimulate respiratory muscles

Question 11

Components of Circulatory Systems

Answer 11

• Once Oxygen diffuses into an animal’s blood it must be transported to the tissues and cells
• Circulatory systems move fluids by increasing the pressure of the fluid in one part of the body
• Fluid flows down pressure gradient
• Made up of:
  – fluid that circulates through the system
  – system of tubes, channels or space
  – pump or propulsive structure

Question 12

Vertebrate Blood

Answer 12

• mammals - 55% plasma, 1% WBC, 45% RBC
• fish - 69% plasma, 1% WBC, 30%RBC

Question 13

Hemoglobin Reversibly binds oxygen

Answer 13

• O2 and Co2 can dissolve in plasma, the amount dissolved is a measure of the gas’s solubility
• Solubility of O2<Co2
• vertebrates and invertebrates evolved hemoglobin
• transportation differs between O2 and CO2
• Cooperative binding - prefers binding at lungs and unloading at tissues

Question 14

Hemoglobin

Answer 14

• Globular protein with 4 subunits
• Each subunit surrounds a heme group with Fe
• Each heme group binds to one O2

Question 15

Open Circulatory Systems

Answer 15

• Blood flows through a vessel with muscular thickenings that act as a pump
• Blood empties into an open body cavity to supply the tissues with nutrients and is returned to the circulation

Question 16

Closed Circulatory System

Answer 16

• Blood flows through connected blood vessels, pumped by the muscular hearts
• Blood flows through vessels to supply tissues with nutrients

Question 17

vessel types

Answer 17

• veins (thinner, deoxygenated blood, moves towards the heart)
• arteries (oxygenated blood, thicker, moves away from heart
• Capillary

Question 18

Pumps- Fish

Answer 18

• Two heart chambers and a single circuit circulation
• Deoxygenated blood enters the atrium from a main vein and then the ventricle
• Deoxygenated blood is pumped from the ventricle into a main artery

Question 19

Land vertebrate circulatory systems

Answer 19

• hearts with more than 2 chambers, which sperate circulation to the gas exchange organs from circulation to the body tissues
• double circuit circulation
• More efficient gas exchange and increases O2 delivery (O2 extracted from air)
• Higher metabolic rates and greater activity

Question 20

Circulation

Answer 20

• In mammals and birds, separated into pulmonary and systemic circuits
• Allows for:
  – increased supply of oxygenated blood to tissues, high pressure
  – increased uptake of O2 at gas exchange surface, low pressure

Question 21

Coordinating Contraction

Answer 21

• Specialized cardiac cells generate action potentials on their own, independently of the nervous system (pace maker, Sinoatrial and atrioventricular nodes)
• Cardiac muscle cells are electrically coupled via gap junctions (transmit electrical signals)
• depolarization in pacemaker results in contraction