1. Circulation and Gas exchange

2. Types of circulatory systems
Diffusion – oxygen and carbon dioxide, based on body shape and size
Gastrovascular cavities – distribution of substances throughout the body and in digestion.
Open circulatory system – arthropods, some molluscs
Hemolymph, interstitial fluid, clear fluid
Pumped through vessels into sinuses and back to heart
Closed circulatory system –
Blood confined in vessles

3. (a) An open circulatory system (b) A closed circulatory system
Figure 34.3
(a) An open circulatory system
(b) A closed circulatory system
Heart
Blood
Heart
Interstitial
fluid
Hemolymph in sinuses
Branch vessels
in each organ
Pores
Dorsal vessel
(main heart)
Figure 34.3 Open and closed circulatory systems
Tubular heart
Ventral vessels
Auxiliary
hearts

4. Cardiovascular system
Closed circulatory system of humans
Arteries – blood away from heart
Capillaries – gas exchange, simple squamous tissue
Veins – blood to the heart
Not all arteries carry oxygenated blood and not all veins carry deoxygenated blood
2 main chambers of the heart
Atrium – receiving chamber
Ventricle – pumping chamber

5. Pulmocutaneous circuit Pulmonary circuit
Figure 34.4
(a) Single circulation: fish
(b) Double circulation:
amphibian
(c) Double circulation:
mammal
Pulmocutaneous
circuit
Pulmonary
circuit
Gill capillaries
Lung
and skin
capillaries
Lung
capillaries
Artery
Heart:
Atrium (A) A A A A
Ventricle (V) V V
Left
Right
Left
Right
Vein V
Systemic
capillaries
Systemic
capillaries
Figure 34.4 Generalized circulatory schemes of vertebrates
Body capillaries
Systemic circuit
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood 5

6. Superior vena cava Capillaries of head and forelimbs Pulmonary artery
Figure 34.5
Superior
vena cava 7
Capillaries of
head and
forelimbs
Pulmonary
artery
Pulmonary artery
Aorta
Capillaries
of left lung 9
Capillaries
of right lung 6 2 3 3 4 11
Pulmonary
vein
Pulmonary
vein 5 1 10
Left atrium
Figure 34.5 The mammalian cardiovascular system: an overview
Right atrium
Right ventricle
Left ventricle
Inferior vena cava
Aorta
Capillaries of
abdominal organs
and hind limbs 8 6

7. Pulmonary artery Aorta Pulmonary artery Right atrium Left atrium
Figure 34.6
Pulmonary artery
Aorta
Pulmonary
artery
Right
atrium
Left
atrium
Semilunar
valve
Semilunar
valve
Figure 34.6 The mammalian heart: a closer look
Atrioventricular
(AV) valve
Atrioventricular
(AV) valve
Right
ventricle
Left
ventricle 7

8. The mammalian heart Approximately the size of a fist
Made of mostly cardiac tissue
Cardiac cycle – one complete sequence of pumping and filling of the heart.
Systole – contraction phase of cardiac cycle
Diastole – relaxation phase of cardiac cycle
Cardiac output – volume of blood each ventricle pumps per minute

9. Valves Atrioventricular – separate the atrium from the ventricle
Bicuspid – mitral valve
tricuspid
Semilunar valves – found at exits of the heart
Pulmonary – leaving heart for lungs
Aortic – leaving the heart to the aorta
Lub Dup
Lub – blood against the closed AV valves
Dup – closing of semilunar valves
Murmurs – abnormal sounds

10. Conduction system
sinoatrial node – pace maker – sets rate and timing of cardiac muscle contraction.
Atrioventricular node – conduct impulses through wall separating atrium and ventricle
ECG – electrocardiogram – graph depicting stages in the cardiac cycle

11. Signals (yellow) from SA node spread through atria. Signals are
Figure 1
Signals (yellow)
from SA node
spread
through atria. 2
Signals are
delayed
at AV node. 3
Bundle
branches
pass signals
to heart apex. 4
Signals
spread
throughout
ventricles.
SA node
(pacemaker) AV
node
Bundle
branches
Purkinje
fibers
Figure The control of heart rhythm (step 4)
Heart
apex
ECG 11

12. Blood vessels 3 layers of tissue
Endothelium – think epithelial tissue
Smooth muscle
Durable connective tissue
Artery – arterioles – capillaries – venules - veins
Arteries and veins differ slightly in structure
Arteries have thicker walls due to higher pressure
Veins have valves to prevent backflow

13. Artery Vein Red blood cells Valve Basal lamina Endothelium Endothelium
Figure 34.9
Artery
Vein LM
Red blood
cells
100 m
Valve
Basal lamina
Endothelium
Endothelium
Smooth
muscle
Connective
tissue
Smooth
muscle
Connective
tissue
Capillary
Artery
Vein
Figure 34.9 The structure of blood vessels
Venule
Arteriole
15 m
Red blood cell
Capillary LM 13

14. Blood pressure
Arterial blood pressure is highest during systole (contraction)
Pulse – rhythmic bulging of the artery walls with each heart beat.
Diastole – relaxation phase, arteries go back to normal, lower pressure

15. Homeostasis To maintain blood pressure as best it can...
Arterioles will dilate or constrict
Endocrine and nervous system will produce Nitric oxide that will induce vasodilation, regulating blood pressure
Gravity – you will faint to get head level to heart, increasing blood flow to brain
Giraffes have higher systolic pressure, 250mmHg
Lymphatic system – gains liters of fluid (lymph) a day begin lost from capillaries.
Lymph nodes – contain cells that destroy bacteria and viruses.

16. Interstitial fluid Blood capillary Adenoid Tonsils Lymphatic vessels
Figure 34.12
Interstitial
fluid
Blood
capillary
Adenoid
Tonsils
Lymphatic
vessels
Thymus
(immune
system)
Lymphatic
vessel
Tissue cells
Lymphatic
vessel
Spleen
Lymph
nodes
Appendix
(cecum)
Figure The human lymphatic system
Masses of
defensive
cells
Peyer’s patches
(small intestine)
Lymph node 16

17. Blood 55% plasma – liquid made of water, proteins, wastes, gas
45% - formed elements
Erythrocytes – red blood cells
Red biconcave disks
No nucleus
Formed in red bone marrow
Leukocytes – white blood cells
Immune system
5 types
Thrombocytes – platelets
Blood clotting

18. Cellular elements 45% Plasma 55% Number Constituent Major functions
Figure 34.13
Plasma 55%
Cellular elements 45%
Number
per L (mm3)
of blood
Constituent
Major functions
Cell type
Functions
Water
Solvent for
carrying other
substances
Leukocytes (white blood cells)
5,000–10,000
Defense
and
immunity
Separated
blood
elements
Ions (blood
electrolytes)
Osmotic balance,
pH buffering,
and regulation
of membrane
permeability
Lymphocytes
Basophils
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Eosinophils
Plasma proteins
Monocytes
Neutrophils
Albumin
Osmotic balance,
pH buffering
Platelets
250,000–400,000
Blood
clotting
Fibrinogen
Figure The composition of mammalian blood
Clotting
Immunoglobulins
(antibodies)
Defense
Erythrocytes (red blood cells)
5,000,000–
6,000,000
Transport
of O2 and
some CO2
Substances transported by blood
Nutrients (such as glucose, fatty
acids, vitamins)
Waste products of metabolism
Respiratory gases (O2 and CO2)
Hormones 18

19. Cardiovascular disease
Disorders of heart and blood vessels
Cholesterol
Atherosclerosis – hardening of the arteries by fatty deposits
heart attack – myocardial infarction – damage or death of cardiac muscle tissue resulting from a blockage of one or more coronary arteries
Stroke – death of nervous tissue in the brain due to lack of oxygen.
Hypertension – high blood pressure – damages endothelium in arteries, promoting plaque build up

20. Gas Exchange
Uptake of oxygen from the environment and the discharge of carbon dioxide to the environment
Respiratory medium – conditions for gas exchange, water or air.
Easier to breath in air, air is less dense and less viscous so easier to move and to force through passageways.
In water, more demanding. Less dissolved oxygen in water compared to air
Warmer and saltier the water, the less oxygen content.
Puts higher energy expenditure on lobsters and fish

21. Respiration surfaces
Cells that carry out gas exchange have a plasma membrane that must be in contact with an aqueous solution.
Exchange takes place by diffusion, proportional to the surface area on which it occurs
Hence why most respiratory organs are folded or branched

22. Respiratory organs
Sponges, cnidarians and flatworms – cells on surface
Marine worms – parapodium – flat appendages
Amphibians, earthworms – skin
Aquatic animals – gills
Insects – tracheal system – network of tubes
Amphibians (limited), most reptiles, birds and mammals depend on lungs

23. Branch of pulmonary artery (oxygen-poor blood) Branch of
Figure 34.20
Branch of pulmonary
artery (oxygen-poor
blood)
Branch of
pulmonary vein
(oxygen-rich
blood)
Terminal
bronchiole
Nasal
cavity
Pharynx
Left
lung
Larynx
(Esophagus)
Alveoli
Trachea
Right lung
50 m
Capillaries
Bronchus
Figure The mammalian respiratory system
Bronchiole
Diaphragm
(Heart)
Dense capillary bed
enveloping alveoli
(SEM) 23

24. Mammalian respiratory system
Nose – filtered , warmed, humidified, and sampled for odors
Larynx
Trachea – windpipe
Bronchi – 2 branches
Bronchioles – branches
Alveoli – simple squamous – diffusion of gas exchange

25. Breathing Alternating inhalation and exhalation of air
Positive pressure breathing – fill lungs with forced air – amphibians
negative pressure breathing – pulling air into the lungs – mammals
Tidal volume – volume of air inhaled and exhaled with each breath

26. Rib cage expands as rib muscles contract. Rib cage gets smaller as
Figure 34.22
Rib cage
expands as
rib muscles
contract.
Rib cage gets
smaller as
rib muscles
relax.
Air
inhaled.
Air
exhaled.
Lung
Diaphragm
Figure Negative pressure breathing
Inhalation:
Diaphragm contracts
(moves down). 1
Exhalation:
Diaphragm relaxes
(moves up). 2 26

27. Control of breathing involuntary
Nervous system – medulla oblongata mainly responsible
Built in buffering system –
Water reacts with water and forms carbonic acid.
Carbonic acid can then dissociate into a bicarbonate ion and a hydrogen ion.

28. Homeostasis: Blood pH of about 7.4 CO2 level decreases. Stimulus:
Figure
Homeostasis:
Blood pH of about 7.4
CO2 level
decreases.
Stimulus:
Rising level of CO2
in tissues lowers
blood pH.
Response:
Signals from
medulla to rib
muscles and
diaphragm
increase rate
and depth of
ventilation.
Carotid
arteries
Figure Homeostatic control of breathing (step 4)
Sensor/control
center:
Aorta
Cerebro-
spinal
fluid
Medulla
oblongata 28

29. Respiratory adaptations of diving mammals
Ex. Weddell seal of Antarctica
Ability to store large amounts of oxygen
Myoglobin – oxygen storing protein found in muscles.
Swim with little muscle movement
Blood supply to muscles can be constricted
Use fermentation rather than respiration