So without further ado, here are my notes so far. There will be a part 2 later on.
1. What are the three layers of tissue that cover the brain? Describe the function of any two of them.
The brain is covered by three layers of tissue known as the meninges.
The outermost layer, the dura mater, is quite hard and offers the most protection of the three layers. It also separates the two halves of the brain by forming a falx cerebri in the middle.
The arachnoid, containing blood vessels and so on, lies underneath the dura mater. It also contains arachnoid villi, which secrete cerebrospinal fluid (CSF).
The innermost layer is the pia mater. This layer is quite thin and is attached to the bain itself.
2. How does the circle of Willis provide insurance against brain infarction?
The circle of Willis, which is essentially a circle of arteries, provides insurance against brain infarction by providing an anastomosis (i.e. if a blockage forms in one part, blood can come in from a different direction).
3. What is the difference between the sympathetic nervous system and the parasympathetic nervous system?
The sympathetic nervous system, located along the spinal cord, is concerned mainly with the fight/flight/freeze survival instincts. The parasympathetic nervous system, on the other hand, is concerned mainly with rest, recovery and regulation.
4. How are the endocrine system and the nervous system different in their regulation of homeostasis?
The endocrine and nervous system are similar in that they both help regulate homeostasis by sending out messages to required parts of the body. They differ, however, in how they send these messages. The chemical-based endocrine system is slower (signalling takes seconds to days) and is less specific, while the electrical-based nervous system is faster (signalling takes only milliseconds) and is very specific.
5. What is the evolutionary purpose of the reflex arc? How might it aid in survival?
The reflex arc reduces the amount of time required for a response to occur. This allows us to avoid dangerous situations or minimise harm done to the body.
6. Describe the steps in the knee jerk (patellar tendon) reflex.
When the knee is tapped, stretch receptors in the muscles send messages to the spinal cord where they are then sent to the brain and to motor neurons. One of these motor neurons sends a message to the femoral muscle to cause the leg to kick out. To stop the hamstrings from tensing up and getting in the way of the reflex action, another motor neuron sends a message to inhibit the hamstrings.
