Circulatory System

1
Circulatory System

• Transport systems in animals

2
Overview

1. Reptiles
2. Birds
3. Mammals

• Functions of a transport/circulatory system
• Cellular transport
• Invertebrate circulation
• Gastrovascular cavity
• Water vascular system
• Open circulatory system
• Closed circulatory system
• Vertebrate circulation
• Fishes
• Amphibians

3
Functions of the circulatory system

• Transports materials
• Nutrients from digested food
• Respiratory gases CO2 and O2
• Waste materials toxins and nitrogenous wastes
• Antibodies
• Hormones
• Enzymes
• Immune functions
• Maintains homeostasis
• Blood pH
• Heat transport

4
Transport at the cellular level

• Cell membrane
• Passive transport (diffusion, facilitated
  diffusion, osmosis)
• high concentration of solutes to low
  concentration of solutes
• no need to expend energy
• Active transport
• spending energy
• moving materials from low concentration to high
  concentration of solutes
• Transport of large molecules
• endocytosis ? vesicles ? exocytosis
• Cyclosis (cytoplasmic streaming)
• occurs in eukaryotes, e.g. Paramecium
• facilitated by microfilaments
• requires energy

5
Transport at the cellular level (cont)

• Endoplasmic reticulum
• manufacturing and transport facility
• proteins produced in rough ER are packaged in
  vesicles
• Golgi apparatus
• modification and storage facility
• receiving end and shipping end
• Vacuole
• large membrane bound sacs
• usually stores undigested nutrients

6
How are materials transported in multicellular
organisms?

• Gastrovascular cavity in simple invertebrates
• No system is required
• Single opening exchange of materials with the
  environment
• Central cavity for digestion and distribution of
  substances throughout the body
• Body walls are two cell layers thick ? materials
  undergo diffusion
• Cnidarians (e.g. Hydra) and flatworms (e.g.
  planarians)

7
How are materials transported in multicellular
organisms?

• Water vascular system in echinoderms
• multi-purpose locomotion, food and waste
  transport, respiration
• closed system of canals connecting tube feet
• madreporite ? ring canal ? radial and lateral
  canal ? tube feet ? ampullae

8
How are materials transported in multicellular
organisms?

• Open circulatory system
• Phylum Arthropoda, Phylum Mollusca (with one
  exception)
• hemolymph (colorless)
• heart(s) ? sinuses ? ostia ? heart(s)
• diffusion from sinuses to organs
• insects well-developed respiratory systems, O2
  not transported through the blood

9
How are materials transported in multicellular
organisms?

• Closed circulatory system or cardiovascular
  system
• cephalopods, annelids, vertebrates
• presence of blood vessels
• advantages
• rapid flow
• may direct blood to specific tissues
• blood cells and large molecules remain within
  vessels
• can support higher levels of metabolic activity

10
General plan of the cardiovascular system

• Heart
• Atrium
• Ventricle
• Blood vessels
• Arteries
• Arterioles
• Capillaries and capillary beds
• Venules
• Veins
• Blood

11
Different adaptations of the cardiovascular
systems in vertebrates fishes

• Single-circulation
• Fish heart
• 2 chambered hearts
• atrium and ventricle
• vessel
• African lungfish heart
• 3-chambered
• 2 atria
• left side of atrium receives oxygenated blood (to
  tissues)
• right side receives deoxygenated blood (to lung
  or gills)
• spiral fold
• partially divided ventricle

12
Different adaptations of the cardiovascular
systems in vertebrates amphibians

• Pulmocutaneous and systemic circulation are
  partly separated
• Amphibian heart
• 1 ventricle pumps blood to lungs, skin, and
  tissues
• 2 atria
• rt. atrium receives deoxygenated blood
• lt. atrium receives oxygenated blood
• advantage oxygen-rich blood reaches the bodys
  organs faster
• some mixing of O2-rich and poor blood occurs

13
Different adaptations of the cardiovascular
systems in vertebrates reptiles

• Reptilian heart
• 3-chambers (except for crocodilians with 4)
• 2 atria
• 1 ventricle (2 ventricles in crocodiles and
  alligators)
• partially divided, decreases mixing
• may stop sending blood to lungs when not
  breathing

14
Different adaptations of the cardiovascular
systems in vertebrates birds and mammals

• 4 chambered heart
• 2 atria
• 2 ventricles
• full separation of pulmonary and systemic
  circuits
• Advantages
• no mixing of oxygenated and deoxygenated blood
• gas exchange is maximized
• separation allows for pulmonary and systemic
  circuits to operate at different pressures
• Importance
• Endothermic ? high nutrient and O2 demands in
  tissues
• Numerous vessels ? great deal of resistance, so
  requires high pressure

15
Blood flow in mammals

• R side of heart
• pulmonary circuit
• L side of heart
• systemic circuit
• one way valves
• atrioventricular valves
• semilunar valves

16
Blood flow in mammals

1. right atrium receives O2-poor blood from superior
   and inferior venae cavae
2. from right atrium into the right ventricle
   through the tricuspid valve
3. pumped into the pulmonary artery through the
   pulmonary semilunar valve to lungs
4. O2-rich blood from lungs is returned to the left
   atrium via the pulmonary veins
5. enters the left ventricle via the mitral or
   bicuspid valve
6. exits the left ventricle into the aorta via the
   aortic semilunar valve
7. circulated to body tissues