Homeostasis within the Circulatory & respiratory Systems

AP Biology:Big Idea #2 & #4Chapter 42

Learning Goals Identify how oxygen and carbon dioxide are

transported and their effects on breathing rate.

Identify a dissociation curve and explain the role of partial pressure of oxygen and oxygen saturation in delivery of oxygen to the body.

Identify and explain how heart rate is controlled.

Identify changes in heart rate and connect to the function of the heart.

Moving GassesDiffusion moves

substances from areas of HIGH to LOW pressure

Gasses dissolve in and out of solution based on partial pressure

Partial Pressure of O221% O2 X 760mmHG =

160mmHG

Partial Pressure Gradients drive the transport of gasses

Partial pressure of gasses varies throughout the circulatory system

Where is ppO2 high? Low?

Where is ppCO2 high? Low?

Role Of Pressure

CO2: Greater at tissues; movement directed AWAY from tissues.

Oxygen: Greatest in alveoli; movement directed toward tissues

Role of Transport PigmentsO2 solubility is low,

therefore plasma alone cannot carry enough

Hemoglobin can carry 4 oxygen atoms each

Note: Hemoglobin saturation (or carrying oxygen) does not change ppO2

Other functions of RBC Fig 42.32Transport of

CO2 Undergoes a

reaction and becomes carbonic acid.

Equilibrium shift @ lungs back to CO2.

Hemeoglobin acts as a buffer

MeasurespO2: partial pressure of oxygen at a

given atmospheric pressure.Saturation of O2: amount of oxygen

bound to hemoglobin

Concentration of O2: dependent on saturation and pressure.

Normal: >95% saturation 100 mm/mg pO2 20 ml/100mL blood

Oxygen Dissociation Curve

• Shows cooperative binding effect, more oxygen = easier binding

• High pressure = high saturation, O2 bound to hemoglobin (Where ?)

• Low pressure = low saturation, O2 released from hemoglobin (Where?)

What happens when the muscles need more oxygen?

Bohr Shift:

Saturation decreased at lower pH.

More O2 falls off blood and enters body tissues.

What do you think the decrease in pH does to hemoglobin to cause this phenomenon?

The Bohr shiftFactors that affect

binding:pH (exercise)temperature

Other binding proteinsMyoglobinFetal Hemoglobin

The High Altitude Problem The concentration of oxygen in air is 20.9%.

Pressure at sea level is 760 mmHg.

1) What is the pO2 at sea level?

2) What changes at high altitude?

3) How does that affect physiology?

4) What changes does the body undergo when it spends weeks at high altitude?

Chemoreceptors detect CO2 levels as first indicator

High CO2 levels normally signal low O2 levels

Underwhat conditions is can receptors be “tricked”?

Backup system: O2 receptors in the heart

How does blood gas affect breathing rate?

Respiratory System Case StudyWhat happens when a person is

afflicted with carbon monoxide poisoning!!!

Discuss answersThis is a practice with multiple

choice!!!

What do you need to know to answer the question?!?

Why are wrong answers wrong and why is the right answer right?!?!

Control of Circulatory SystemBlood pressure

Heart Rate

Blood Pressure

What do the values tell us?

Review: Arteries and VeinsArtery: Away Vein:

Towards

Review: Heart/Lung Circulation

Structure meets functionReview: What is an intercalated disk? What is a gap junction?

What signals muscles to contact? Cardiac muscles?

Nervous Control

Heart Rate and Pacemaker

EKG with Letters

Abnormal heart RhythmsDescribe and Draw each of the abnormal heart

rhythms:

Atrial FibrillationTachycardiaBradycardiaVentrilcular Fibrillation

Then, write a case study for a patient and have a partner determine which rhythm he/she would likely experience.