Geek Out: Biceps Curls, Banjo Playing And Bladder Control …

To the spinal cord:

Any information about the state of the body below the head, is going to have to travel to the brain vis the spinal cord however, information from and control of structures in the head, occurs through a direct nerve, brain, nerve circuit.

It’s logical when you think about it. Being able to smell things requires information to travel directly from the nose, via neurons to the brain – it wouldn’t make sense to route that information from the nose, to the spinal cord and then up to the brain.

Similarly, as your brain regulates your eye movements for you to scan this page, the commands that travel to your ocular (eye) muscles travel the shortest route – brain, ocular nerves, eye muscles, routing those signals via your spinal cord would make no sense at all!

 Upwards/down:

Most of the time our brain is the highest point of our nervous system as we’re sitting or standing.  If we’re lying down, of course our nervous system is still functioning and information is passing along the spinal cord to/from the brain

Tag:

Label in Brit speak!

Pre-programmed value:

We have pre-sets for all sorts of things, ranging from blood pressure to appropriate blood carbon dioxide level to body temperature.  Our brain’s constantly comparing our actual blood pressure, blood CO2, body temperature to these pre-set values and if they don’t match, action will be taken such as squeezing blood vessel walls together, changing breathing rate or making us shiver!

Lung-inflating muscles:

To be absolutely clear here, the lungs don’t contain muscles however, the diaphragm (a thick sheet of muscle that separates the chest region (thorax) from the abdomen) and the muscles that run between adjacent ribs can be commanded by the brain to contract.  When that happens this allows the lungs to inflate (by some rather clever physics/chemistry, a topic for another day).

Leg:

Strictly speaking, the leg isn’t quite what you think it is.  An anatomist or orthopedic surgeon (if they’re speaking with colleagues) will refer to the region from hip to ankle as the lower extremity, the thigh as the thigh and your calf region i.e knee to ankle only, as the leg.  How confusing!

These nerves:

I’m sure you all realized this but these nerves come in matching pairs so there’s a left sciatic nerve for the left leg and a right sciatic nerve, you get the idea.

Voluntary:

also called somatic motor system as “soma” is Greek for body

Every nerve:

All the nerves supplying structures below the head, are two-way nerves.  A few of the cranial nerves, nerves which supply the eyes, nose and other structures above the neck carry only one type of information, input or output.

Bundle of neurons:

If we cut open a nerve we’d see lots of what look like very, very thin threads – these are the long tails of our neurons, each one’s called an axon.  Nerves typically are made up of thousands of neuronal axons

Neuron types:

Neurons that regulate skeletal muscles are called somatic motor neurons.

There are actually several different types of neurons that get involved in letting the brain know how heavy a weight is and how hard a muscle’s working – some of these will be sensory neurons in the muscles, some will be sensory neurons in the tendon attaching a muscle to a bone.

Chemicals:

Because these chemicals are responsible for the transmission of information through our nervous system, that’s why they’re collectively called “neurotransmitters”

Between:

The brain’s neurons use these same chemicals and electrical signals to chat to each other to solve our math homework, they’re just not bundled together in nerves.

Billions of neurons:

Estimates suggest we have 80ish billion neurons in our brain but probably as important as the number of neurons, is the number of connections between these neurons.  Brain researcher, Dr. Susan Greenfield equated the number of neurons in our brain to the number of trees in the Amazonian rain forest and added that the number of connections between our neurons is close to the number of leave on those Amazonian rain forest trees.