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Ein-O Facts •An adult brain weighs about 1.5 kg (3.3 lbs). •The brain contains more than 10 billion neurons.
At birth, the brain has many folds which show that it is developed.
•Frontal lobes Voluntary movements are controlled by a part of the frontal lobes. Speech is also controlled by two main regions of the brain in the frontal lobes.
Messages are sent to and from your brain by nerves. Nerves connect every part of your body with your brain. They act like an electrical wire, letting your brain know what is happening to you.
•The brain needs a good supply of blood to provide food and oxygen to maintain its activity. If the blood supply is cut off for just a few seconds, a person becomes unconscious. And if the blood supply is not quickly restored, permanent brain damage will occur.
External Features of the Brain The human brain looks similar to a huge walnut or cauliflower, with a wrinkled surface split into halves. The following are six major external features of the brain:
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2 EIN-O’s INTRO
Even though there is an incredible variation in body shapes and sizes, all humans share common features and the same working parts. The human body is built from trillions of cells. Similar cells group together to form tissues (a Latin word that means “woven”). Types of tissues include nervous tissue, muscle tissue, connective tissue and epithelial tissue. And when tissues group together, they can make organs that pump blood (heart), digest food (stomach) and breathe air (lungs). The Bio Signs series is an assortment of 6 human anatomy models. The detailed models are the: Brain and Skull, Eye, Head and Torso, Heart, Skin, and Teeth and Gums.
This I Know Guide provides an introduction to: the Brain & Skull
BRAIN & SKULL The BRAIN is our largest and major organ of the central nervous system. It is one of the first organs to develop before birth. The brain is responsible for our thoughts, memory logic, movement, emotion, and language. Among many responsibilities, it enables us to eat, walk, speak, think and act.
5 •Temporal lobes Noises picked up by our ears goes to the temporal lobes. This area enables us to process languages and to make up our replies. •Brainstem The brain stem plays a vital role in basic attention, arousal, and consciousness. All information to and from our body passes through the brain stem on the way to or from the brain. •Parietal lobes Sensation is processed by an adjacent part of the brain in the parietal lobes. •Occipital lobes Our sense of vision is processed in the occipital lobes. This area also helps us to understand language.
6 •Cerebellum Its main functions are to control muscles, keep our bodies in balance, maintain posture and coordinate body movement.
7 underneath your skin made from bone.
Two sets of bones The skull is made up of two sets of bones: •the bones of the face, and •the bones of the cranium, which make up your forehead and the back of your head.
SKULL
Facial bones
The SKULL protects the brain, as if it were a safety
There are 14 facial bones at the front of the skull. These hold the eyes in place and form a person’s facial features. The mandible, or jawbone, is
9 the largest, strongest bone in the face. It holds the lower teeth in place and helps a person to chew food. Apart from 2 bones, all the facial bones are arranged in pairs. This is why the face is symmetrical.
The Brain and Age
Cranium
Our brain’s weight is related to our body’s weight. Therefore, large people have relatively larger brains than small people. However, this does not mean that bigger people are brainier than smaller people!
The cranium is the large bony case that surrounds your delicate brain, protecting it from bumps and knocks. It is made up of 8 large flat bones, joined together by fixed joints known as sutures. The frontal bone forms the forehead, and the tops of the eye sockets. Most of the top and sides of the head are formed by two parietal bones. The back of the skull is formed by the occipital bone which has an opening, called the foramen magnum, where the spinal cord connects to the brain.
The brain grows rapidly during infancy. Brain weight increases from about 350 grams at birth to about 1.3 to 1.5 kg, and then slowly declines during old age. The change in brain weight and volume is probably caused by the loss of neurons (nerve cells).
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10 From flexible to fixed joints A human skull is almost full sized at birth. However in a newborn, the 8 bones that make up the cranium are not yet fused together. This means that the skull can flex and deform during birth, making it easier to deliver a baby through the narrow birth canal. These individual plates of bone fuse together after about 24 months to form the adult skull.
Ein-O Facts •The only bone in your skull that forms freely movable joints is the mandible, or jawbone. •The frontal bone forms your forehead and the roof of your eye sockets.