The Brain

The human brain is the most complex organ in the human body. We can subdivide it into several anatomically distinct areas. Each of them fulfills specific functions. Overall, the brain comprises 6 basic parts: the medulla, the pons, the cerebellum, the midbrain, the diencephalon and the cerebrum.

Medulla Located at the lower part of the brain stem, it forms the junction between the brain and the spinal cord. It contains many visceral reflex centers. The medulla regulates breathing, swallowing , sneezing , coughing , digestion, and regulates your heart rate. Without the medulla, life would be impossible; it regulates blood pressure and breathing. It is the most important part of the brain and, as a part of the brainstem, helps to transfer neural messages from the brain to the spinal cord.

Pons The pons connects the upper and lower part of the brain and is located between the medulla and the midbrain. Within the pons are two respiratory centers; together with the medulla they regulate the breathing rhythm. The pons plays a key role in sleeping and dreaming (REM sleep) also helps to pass information between the cortex and the cerebellum.

Cerebellum Located at the lower area of the brain (below the pons), the cerebellum is responsible for the balance, coordination of body movements, and for posture maintenance. The cerebellum receives various sensory inputs from the visual system, the inner ears and from the somatosensory system. It compares this sensory information with intended movements, represented as commands from the motor cortex. An example: if you decide to pick up a pencil, the impulses for the arm movements come from the cerebral cortex and the cerebellum modifies these impulses with respect to the actual movement that is performed (and e.g., seen by your eye). Patients with an injured cerebellum often struggle with keeping their balance and maintaining etw. unterstützen proper movement coordination.

Midbrain The midbrain (or mesencephalon) lies between the pons and the hypothalamus (see below) and encloses the cerebral aqueduct. The midbrain contains the superior and inferior colliculi (together termed, the “tectum”, Latin for: roof). The inferior colliculus is important for the auditory system, while the superior colliculus processes visual information. As an example: a person sees a wasp flying towards them and automatically dodges away. This is a visual reflex (coordinated movement of the eyeballs). Turning ones head towards a sound is an example of an auditory reflex. In the midbrain, the reticularis formation controls arousal levels and controls motor and sensory systems.

The midbrain, pons and medulla are often classified together as the brainstem .

Diencephalon The diencephalon is divided into the hypothalamus and the thalamus.

The hypothalamus is a small part of the brain and is located above the pituitary gland and below the thalamus. It is responsible for homeostasis (hunger, thirst, thermoregulation). It is also important for the production of antidiuretic hormone (ADH), which enables the kidneys to reabsorb water back into the blood and helps maintain the blood volume. It also produces oxytocin, which (among many other functions) causes contractions of the uterus to bring about labor and delivery. The hypothalamus produces growth hormone releasing hormone (GHRH), which stimulates the anterior pituary gland to secrete growth hormone (GH). The hypothalamus also controls sexual behavior and regulates emotions.

The thalamus is located below the corpus callosum. The functions of the thalamus are concerned with sensation. It is a relay station for various sensory information transmitted from the sensory centers (auditory, visual, tactile and gustatory) to the respective parts of the cerebral cortex. It also suppresses non-essential sensations. E.g. if you are reading an enjoyable book, you may not notice someone coming into the room. By temporarily blocking minor sensations, the thalamus permits the cerebrum to concentrate on important tasks. If a patient has injured this part of the brain, all sensory information would not be properly processed and sensory confusion would result.

Cerebrum This is the largest part of the human brain and consists of two hemispheres separated by the longitudinal fissure. The surface of the cerebrum is the grey matter called the cerebral cortex. Below the grey matter is the white matter. This connects the lobes of the cerebrum to one another and to all other parts of the brain. The cerebral cortex existensively folded. These folds are called gyri, and the grooves between them are fissures (or “sulci”). This folding greatly increases the surface area of the brain, thereby permitting the presence of millions more neurons and synapses within the cerebral cortex.

The cerebral cortex is divided into lobes that have the same names as the cranial bones external to them: Frontal Lobes, Parietal Lobes, Temporal Lobes, Occipital Lobes . Each of the various cortical lobes serve certain cognitive tasks.

Corpus Callosum:

At the base of the cerebrum is the corpus callosum, a band of about 200 Mio neurons that connects the right and left hemispheres.

Associative Cortex:

This is the area what truly makes us individuals. This area is not concerned with movement or a particular sensation. This area gives us personality, a sense of humor, and the ability to reason and use logic. Also, learning and memory are functions of these area.

Basal Ganglia:

These are paired masses of grey matter within the white matter of the cerebral hemispheres. Basal ganglia help to control the bodily movements. The best known disorder of the basal ganglia is Parkinson’s disease.

Ventricles Located within the brain parenchyma, ventricles are a series of interconnected fluid-filled cavities. They are a communicating network of spaces in the brain and are filled with cerebrospinal fluid (CSF). CSF is the tissue fluid of the central nervous system that circulate within the ventricles and is formed from blood plasma. There are four main cavities within the brain: two lateral ventricles, the third ventricle (the cerebral aqueduct) and the fourth ventricle. The ventricular system is continuous with the central canal of the spinal cord. Each ventricle contains a capillary network called choroid plexus, which forms CSF from blood plasma.

BIBLIOGRAPHY 1. Patestas MA, Gartner LP: A Textbook of Neuroanatomy, 2nd edition, Wiley Blackwell, 2016. 2. http://dict.leo.org. 3. www.dict.cc. 4. www.webster-dictionary.org.

EXERCISE: 1. When could the patient have difficulties after cerebellum damage? a. Playing baseball on a field b. Running in a race or marathon c. Swimming in a pool d. Singing a song e. Talking to a friend

2. Fluid filled cavities (within the brain) are called a. ventricles b. meninges c. cavities

3. Which part of the brain controls emotional experiences? a. hypothalamus b. medulla c. temporal lobe d. pia mater

You’ll find the answer on: http://tinyurl.com/weiterbildung-englisch

Die Autorin: Carmen Lobitz Carmen Lobitz ist freie Trainerin, Lehrerin und MTA. Sie gründete 1998 in Berlin lobitz seminare, die unter anderem Englischseminare für Health Professionals anbieten. Kontakt: mail@lobitz-seminare.de, www.lobitz-seminare.de

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Lösung für Exercise: Answer: 1. a, b, c Answer: 2. a Answer: 3. a

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