Human Anatomy: Cerebellum, Liver, Medulla, Spinal Cord, and Heart
Cerebellum
The cerebellum is a region of the brain whose main function is to integrate sensory and motor pathways. There are a lot of nerves that connect the cerebellum to other brain structures and the spinal cord. The cerebellum integrates all information received to refine and control commands sent to the cerebral cortex’s locomotor pathways. The cerebellum is an unpaired organ, located in the posterior cranial fossa, dorsal to the brainstem, and below the occipital lobe. It has a central portion, the vermis, and two much larger portions that straddle it, the hemispheres.
Liver
The liver is an organ present in vertebrates and some other animals. It is the most voluminous gland of the anatomy and one of the most important in terms of the body’s metabolic activity. The liver plays unique and vital functions such as the synthesis of proteins, detoxification, and storage of vitamins and glycogen, among others, for the proper functioning of the body’s defenses. It is also responsible for removing substances from the blood that may be harmful to the body, transforming them into harmless ones. The liver is ovoid, elongated transversely, and reddish-brown. It consists of a parenchyma surrounded by a thin fibrous capsule called Glisson’s capsule. In adults, it measures approximately 28 by 15 cm anteroposteriorly and 8 cm thick in the right lobe, weighing approximately 1500 g.
Medulla Oblongata
The medulla oblongata is the lowest of the three segments of the brainstem, between the pons (above) and the spinal cord (below). It takes the form of a truncated cone with a bottom point, approximately three inches long. Its boundary with the spinal cord is not well-defined but is given by the emergence of the highest radicle of the first cervical nerve at the height of the bottom edge of the foramen magnum. The medulla oblongata is responsible for the transmission of impulses from the spinal cord to the brain. Injury to the medulla oblongata causes immediate death by cardiac or respiratory arrest. It also regulates heartbeat, breathing movements, and the secretion of digestive juices.
Spinal Cord
The spinal cord is the region of the central nervous system housed in the spinal canal. It is responsible for carrying nerve impulses to the spinal nerves to supply the brain with information from the body. It has two basic functions: the afferent function, in which sensory sensations from the trunk, neck, and four extremities are carried to the brain, and the efferent function, in which the brain directs the body’s effectors to perform a certain action, taking these impulses to the trunk, neck, and limbs. The spinal cord also controls immediate movement and vegetative functions, such as reflexes, the sympathetic nervous system, and the parasympathetic nervous system. In its development, the spinal cord reaches a length of 50 cm in men and 43 cm in women, with a weight of 568 grams.
Heart
External Configuration
- Anterior (Sternal): Consists mainly of the right ventricle.
- Diaphragmatic (Lower): Essentially set up by the left ventricle and partly by the right; it relates basically to the central tendon of the diaphragm.
- Pulmonary (Left): Consists almost exclusively of the left ventricle.
- Right Border: Formed by the right atrium and extends between the superior vena cava and inferior vena cava.
- Inferior Border: Almost horizontal, mainly composed of the right ventricle and a small part of the left ventricle.
- Left Border: Formed mainly by the left ventricle and part of the left auricle.
- Superior Border: Formed by the left and right atria; the ascending aorta and pulmonary trunk emerge from here, whereas the superior vena cava enters on the right side.
Internal Configuration
The heart is divided into two halves, right and left, by the septum. Each side of the septum has two chambers: an atrium and a ventricle, separated by the atrioventricular orifice and provided with an atrioventricular valve.