Tonsillar artery

Wednesday, December 6, 2017

The tonsillar artery arises from the facial artery, which, in turn, comes off the external carotid artery. From its point of origin, it runs up between the styloglossus and pterygoideus muscles at the base of tongue, dividing into smaller-caliber blood vessels. The tonsillar branch of the facial artery supplies the tonsils and the root of the tongue.

Tongue innervation

Tuesday, December 5, 2017

The muscles of the tongue (styloglossus, genioglossus, hyoglossus, superior longitudinal and inferior longitudinal) are innervated by the hypoglossal nerve (CN XII), from which arise motor efferent nerve fibers that supply them all. The hypoglossal has only motor function and has its center in the hypoglossal nucleus in the medulla oblongata.

See deglutation reflex

Fat does not make you fat, and it is healthy.

Sunday, December 3, 2017

Fat does not make you fat. I mean, when you eat dietary fat, that fat (from animal or seeds) does not make you obese. Why? Because it does not increase your glucose levels in your blood. This sudden increase in sugar in your blood only happens when you eat carbohydrates. All types of carbs make your glucose levels in your blood go up, and in order to lower them to normal levels, insulin, which is a hormone secreted by the pancreas, induces your tissues to store this excess glucose as body fat. It has to be lowered because high glucose content is inflammatory for the body tissues. Thus, you get fat only when you eat carbohydrates and lead a sedentary life. However, this does not happen when you eat fat (butter, tallow, lard, oil, etc), because it does not get converted into glucose, but it gets broken down into glycerol and fatty acid by lipase, which is an enzyme secreted by the exocrine pancreas and the liver.

Let us suppose you are an ordinary guy that eats a lot of carbs, but one day there is a famine period and you are forced to go into a prolonged period of fasting. When you run out of glucose and glycogen (compressed glucose stored in the liver), your muscle cells and brain neurons start using fat for energy but in the forms of fatty acid and ketone bodies (derived from fatty acid) respectively as fuel instead of glucose. This is means that you are burning fat, and when you are burning fat for fuel, it is said that you are in ketosis, that is to say that your brain cells are using ketone bodies for fuel. Ketone bodies derive from fatty acid, which in turn comes from fat, be the fat stored in your body or the dietary fat you begin to eat when you are forced to hunt animal for living. Ketone bodies promotes the biogenesis of the mitochondrion in the nerve cell, which in turn induces the neurogenesis of neuron, especially in the hippocampus region of the brain.

Blood supply to the basal ganglia

Tuesday, November 21, 2017

The basal ganglia, which are grey structures at the base of the brain, are supplied by the lenticulostriate arteries, also called anterolateral central arteries. These oxygen-rich blood vessels arise from the M1 segment of the middle cerebral artery, which, in turn, originate from the internal carotid artery. They are between three and five branches that come off the middle cerebral artery and run upwards in each cerebral hemisphere.

Foramen transversarium

Wednesday, November 15, 2017

The foramen transversarium, or transverse foramen, is one of two orifices that are found in the transverse processes on each side of the seven cervical vertebrae (neck region). The function of these small openings in the vertebrae processes is to lodge and protect each of the two vertabral arteries, which run through them upwards until they enter the skull through the foramen magnum. The vertabral arteries arise from the subclavian arteries and join together in the base of the skull to form the basilar artery.

Transverse foramen in cervical vertebra

Transverse foramina lodging the one of the vertebral arteries in the neck.

Foramen spinosum

Thursday, October 19, 2017

The foramen spinosum is a paired orifice, which is found on the greater wing of the sphenoid bone, one on each side of the base of the skull. In other words, it is located anteriorly to the sphenoid bone spine. Function: the foramen spinosum serves as a passageway to the nervus spinosus, which is the meningeal branch of the mandibular nerve, and to the middle meningeal artery. The nervus spinosus innervates the meninges, and the middle meningeal artery supplies the dura mater.

Location of the foramen spinosum in the base of the human skull
image from usf edu

Zygomatic arteries

Wednesday, October 18, 2017

The zygomatic arteries are oxygen-rich blood vessels that originate from the lacrimal artery, which, in turn, arises from the ophthalmic artery. They are usually two branches that come off as lateral projections of the lacrimal. Then they further fork into smaller caliber vessels. Function: they supply the zygomatic bone and other structures.