In the first article about the kidneys, we learnt how blood is filtered and substances are reabsorbed in the Bowman's capsule and 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. The loop of Henle, distal... Continue Reading →
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 →
We know that nerve impulses are carried along neurones in a wave of depolarisation. But how does a nerve impulse get transmitted from one neurone to the next? Well, that is where synapses come in. Structure of synapses Synapses are the microscopic gaps between neurones. The neurone before the synapse is called the presynaptic neurone,... Continue Reading →
Last time we looked at an action potential happening in a section of a neurone cell membrane. The membrane was depolarised and repolarised. However, that depolarisation must travel along the whole length of a neurone in the right direction. Today we will look at how an action potential travels in a wave of depolarisation. The... Continue Reading →
In the last article we learnt that neurone cell membranes are polarised at rest (when they are not being stimulated). However, when a stimulus is detected a nerve impulse must be sent along the neurone. Today we will look at the sequence of events that happens during an action potential and how ion channels bring... Continue Reading →
The nervous system communicates information by sending nerve impulses. In the last article we saw how impulses are generated at receptors in response to a stimulus. Now the impulses must be transmitted by neurones. In this article we will look at some of the different types of neurones found in the nervous system, and see... Continue Reading →
In the last post we looked at the structure of the xylem vessels, so now we're going to take a look at their function. Water transport in plants happens up the xylem vessels in a transpiration stream from roots to leaves due to the properties of water and transpiration at the leaves. Let's break the... Continue Reading →
So far in the exchange and transport series we have mainly been looking at exchange and transport of gases. However, organisms also need to absorb nutrients such as glucose and amino acids so they can carry out processes like respiration and protein synthesis. In this article we will cover how large food molecules are broken... Continue Reading →
Getting blood around the body requires a network of blood vessels. These come in different shapes and sizes depending on their location and function. In this article we will look at the structure of arteries, veins, capillaries. Arteries Arteries carry oxygenated blood away from the heart to the tissues of the body (except the pulmonary... Continue Reading →
Fish and insects don't have lungs like humans and other mammals do. Instead, they have clever alternative gas exchange systems in order to deliver oxygen to their cells. Let's look at each organism individually. Gas Exchange in Fish I'm sure it's fairly obvious that fish don't breath air because they live underwater. Instead, they must... Continue Reading →
