Compendium 9 - How does it all work?

The spinal cord can be divided into Five regions: cervical, thoracic, lumbar, sacral
and coccygeal

There are 31 pairs of spinal nerves

There are 29 pairs of spinal nerves

The top half of spinal cord consists of the Cervical and Thoracic nerves

The Conus medullaris is the lower, bulgey and spongey part of the spinal column

The Cauda Equina is a collection of nerve root posterior of the spinal cord, which are horsetail-like in appearance.

The Pia mater has many small blood vessels

The Dura mater has subdural space and serous fluid

The Pia mater has subdural space and serous fluid

Spinal nerves contain sensory neurons and motor (somatic and autonomic) neurons

Endoneurium surrounds each axon and its associated Schwann cells.

The Endoneurium is a layer of delicate connective tissue that encloses the myelin sheath of a nerve fiber.

The Perineurium is the sheath of connective tissue surrounding a bundle (fascicle) of nerve fibres within a nerve

The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve. It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the perineurium.

The Midbrain, Pons and Medulla Oblongata make up the brain stem

The Pons serves as a message station between several areas of the brain. It helps relay messages from the cortex and the cerebellum. Without the pons, the brain would not be able to function because messages would not be able to be transmitted, or passed along. It also plays a key role in sleep and dreaming, where REM sleep, or the sleeping state where dreaming is most likely to occur, has been proven to originate here, in the pons.

The Pons connects upper and lower parts of the brain

Non-tropic hormones are hormones that directly stimulate target cells to induce effects. This differs from the tropic hormones, which act on another endocrine gland. Non-tropic hormones are those that act directly on targeted tissues or cells, and not on other endocrine gland to stimulate release of other hormones.

A tropic hormone is one that acts on another endocrine gland, which then produces another hormone.

The anterior pituitary is the main gland that produces tropic hormones. Because the anterior pituitary produces hormones that influence other endocrine glands, we often call it the master gland

Most hormones are steroid or amino acid based molecules

What are the functions of the hypothalamus?
1. Coordination of autonomic reflexes, e.g. changes in blood pressure, digestive functions, filling / emptying of bladder and defecation
2. Controls sleep patterns, satiety and hunger
3. Regulation of emotions
4. Regulation of food and water intake
5. Influences hormone release from pituitary gland
6. Stimulates sexual development, arousal and behaviour
7. Regulates body temperature

What are the functions of the cerebellum?

Control of balance, eye movements, posture, smooth locomotion, proprioceptive information from muscles and joints (informs brain about stretch and tension of muscles and positions of joints) and planning movements