Dissectible Me 5 minute anatomy

The blood brain barrier describes how the endothelial cells of the capillaries in the brain are tightly stuck together by tight junctions, wrapped in the feet of astrocytes and lined by a basement lamina. This stops most molecules from moving between the blood and the brain through any gaps. Instead, transporters are needed to transport molecules across the endothelial cells. Why does this happen in the brain? How does ethanol get to the brain? 

The brain has spaces inside it, interconnected and filled with cerebrospinal fluid. This fluid is continually produced here and flows from chamber to chamber, sometimes through narrow passageways, until it leaves to surround the brain and spinal cord. 

Cerebrospinal fluid surrounds the brain, brainstem and spinal cord, it fills spaces within them, is continually produced and drained away, but why? 

The muscles that flex and extend the elbow joint. Biceps brachii, brachialis, triceps brachii, anconeus and brachioradialis. What they attach to, how they move the bones and the nerves that innervate them in 5 minutes(ish). 

The term "brain death" can be used to refer to irreparable damage of the brainstem or cerebrum. By considering the differing functional anatomy of the brainstem and the cerebrum we can more clearly understand what type of injury is being referred to when this term is used in relation to a particular person. Functional neuroanatomy also helps us understand why movement of the eyes, groaning, and even movement of the limbs can still occur in some cases of brain death. 

The midbrain is the upper part of the brainstem. In here we find tracts running to and from the spinal cord and cerebrum. We find nuclei and groups of neurones such as the substantia nigra, red nucleus, periaqueductal grey, colliculi and reticular formation. Cranial nerves III and IV come out of the brainstem. What do all of these things do? What does all this mean? 

Quadriceps femoris and the hamstrings are powerful extensors and flexors of the knee respectively, but they also cross the hip joint. Let's talk about their anatomy. 

The pelvic floor (or pelvic diaphragm) describes the structures at the lowest point of the pelvis, largely muscles, that support the pelvic organs directly and everything else inside the torso. Let's explain concisely the important anatomy here.

The flexor tendons of the fingers run into synovial tunnels that let them move freely as we strengthen and relax our grip. These tunnels are tied down to the bone by some extraordinarily strong annular and cruciform pulleys that keep the tendons close to the bone. Let's describe their anatomy and their naming. 

There are 3 arches in the foot: a medial longitudinal arch, a lateral longitudinal arch and a transverse arch. Why do humans have arches in their feet? What's the anatomy here?