Archive for March, 2012

H6 Gas exchange

Wednesday, March 14th, 2012

You need to get your head around this.  Gas Exchange     The effect of exercise on heart and lungs    And here’s a great presentation to help.

  • Define partial pressure.
  • Explain the oxygen dissociation curves of adult hemoglobin, fetal hemoglobin and myoglobin.
  • Describe how carbon dioxide is carried by the blood. [Include action of carbonic anhydrase, chloride shift, and plasma proteins]
  • Explain the role of the Bohr shift in the supply of oxygen to respiring tissues.
  • Explain how and why ventilation rate varies with exercise.
  • Outline the possible causes of asthma and its effects on the gas exchange system.
  • Explain the problem of gas exchange at high altitudes and the way the body acclimatizes.

H5 Transport system

Monday, March 12th, 2012

Cardiac_Cycle_Left_Ventricle from wikimedia

Take another look at your notes on blood, blood vessels and the heart from topic 6.  Re-learn your heart diagram.  There is some new vocab to get your head around in this section.  I have highlighted these terms below.  Use this presentation to help you.

Here are some useful animations for the cardiac cycle.

Phases of the cardiac cycle

The cardiac cycle

  • Explain the events of the cardiac cycle. [Talk about atrial and ventricular systole and diastole, and heart sounds]
  • Analyse data showing pressure and volume changes in the left atrium, left ventricle and aorta during the cardiac cycle.
  • Outline the mechanisms that control heartbeat. [Include role of sinoatrial (SA) node, atrioventricular (AV) node and conducting fibres in the ventricular walls]
  • Outline atherosclerosis and the causes of coronary thrombosis.
  • Discuss factors that affect the incidence of CHD (coronary heart disease).

Functions of the liver

Friday, March 9th, 2012

BIO 120 liver 010 by djneight on flickr

Here are a couple of presentations for you. Functions of the liver  and this one.  You should be able to:

  • Outline the circulation of blood through liver tissue, including the hepatic artery, hepatic portal vein, sinusoids and hepatic vein.
  • Explain the role of the liver in regulating levels of nutrients in the blood.
  • Outline the role of the liver in the storage of nutrients, including carbohydrate, iron, vitamin A and vitamin D.
  • State that the liver synthesizes plasma proteins and cholesterol.
  • State that the liver has role in detoxification.
  • Describe the process of erythrocyte and hemoglobin breakdown in the liver, including phagocytosis, digestion of globin and bile pigment formation.
  • Explain the liver damage caused by excessive alcohol consumption.

Past Paper Practice

Tuesday, March 6th, 2012

Past paper multiple choice practice: Biology HL paper 1   Answers here: Biology HL paper 1

Past paper extended response question practice: May 03 Extended Response Qs        Nov 04 Extended Response Qs

And here are the answers: MAY 2003 Paper 2 SECTION B Marker        NOV 2004 Paper 2 SECTION B Marker

Option H – Hormonal control

Friday, March 2nd, 2012

As we delve into Option H, we’ll be reviewing human biology concepts at the same time.  This first section is about hormonal control.  Hormones are chemical messengers secreted by endocrine glands into the blood and transported to specific target cells.  They can be steroids (eg progesterone, testosterone, estrogen), proteins (eg insulin, ADH, FSH, LH) and tyrosine derivatives (eg thyroxin).

You need to:-

  • Distinguish between the mode of action of steroid and protein hormones.
  • Outline the relationship between the hypothalamus and the pituitary gland.
  • Explain the control of ADH (vasopressin) secretion by negative feedback.

Another fantastic presentation here.  We’ll use this one too. Hormonal Control