Cardiovascular disease is a non-communicable disease; it is not caused by a pathogen and cannot be passed from person to person. Most cardiovascular disease begins with atherosclerosis developing in an artery due to factors such as high blood pressure. In this article we will look at how atheromas develop, cardiovascular disease risk factors, and treatments.... Continue Reading →
Codominance and Multiple Alleles – Inheritance Ep 2
In the last article we looked at inheritance of a characteristic coded for by a single gene which has one dominant allele and one recessive allele. However, sometimes alleles can be codominant or there can be more than two alleles for a gene. This increases the number of possible phenotypes. Let's look at each case... Continue Reading →
Control of Blood Water Potential – Homeostasis Ep 6
In the first article about the kidneys, we learnt how blood is filtered in the Bowman's capsule and how some substances are reabsorbed in the proximal convoluted tubule. Today we will focus on the loop of Henle, distal convoluted tubule, and collecting duct, and look at how blood water potential is controlled using negative feedback.... Continue Reading →
Ultrafiltration and Selective Reabsorption in The Kidneys – Homeostasis Ep 5
The kidneys are important organs for maintaining blood water potential and excreting waste products from the blood. In this article, we will look at the structure of the kidneys and how substances are filtered out and reabsorbed into the blood using ultrafiltration and selective reabsorption. Kidney structure The kidneys have an outer layer called the... Continue Reading →
Control of Blood Glucose – Homeostasis Ep 3
Control of blood glucose is very important. Sufficient glucose must be delivered to cells for respiration, but too much glucose can eventually result in coma or even death. The concentration of glucose in the blood is affected by factors such as eating and exercise, and must be brought back to the normal level of about... Continue Reading →
Feedback Mechanisms – Homeostasis Ep 1
Homeostasis is the maintenance of a stable internal environment. The conditions inside the body must be stable so that cells can function properly. For example, if the temperature or pH are too high, enzymes can become denatured. It is also important to maintain blood glucose concentration and blood water potential, which we will look at... Continue Reading →
Barriers to Infection – Immunity Ep 5
In order for a pathogen to enter the body and cause a disease, it must pass through the body's non-specific defences. The barriers to infection are non-specific because they respond to all pathogens in the same way. Infection routes There are four main routes with a pathogen can take to enter the body: The digestive... Continue Reading →
Developing Immunity – Immunity Ep 2
In the last article we looked at how the immune system responds to a pathogen which is encountered for the first time. This is the primary immune response. However, if the same pathogen enters the body again in the future, the immune system is able to respond more quickly because it is prepared. In this... Continue Reading →
The Immune Response – Immunity Ep 1
Sometimes the body comes under attack from pathogens (microorganisms that can cause disease). If pathogens get into our body, it is down to our immune system to spring into action and destroy them. In this article we will be looking at how foreign antigens trigger our immune response, and how that results in the pathogens... Continue Reading →
Haemoglobin – Exchange and Transport Ep 12
In the last article I mentioned that red blood cells contain a protein called haemoglobin. In simple terms, the haemoglobin protein binds to oxygen and transports it around the body. As with most of biology there's a bit more to it than that, so here we will look at how this process works in more... Continue Reading →
