Ear

The ear is the organ of hearing and equilibrium (balance) in vertebrates. The ear converts sound waves in the air to nerve impulses that are relayed to the brain, where they are interpreted as sound rather than as mere vibrations. The innermost portion of the ear maintains Biological Equilibrium through the so-called vestibular apparatus, which includes the semicircular canals. Any change in the position of the head or body causes the apparatus to transmit nerve impulses to the brain, evoking muscular apparatus is basically alike in all vertebrates; hearing structures evolved later in the higher vertebrates.

Many vertebrates also have specialized sense organs, rather than ears, for hearing and equilibrium. Crickets and spiders, for example, have membranes much like sounding boards on the legs. Moths have a similar rudimentary ear on the thorax that apparently serves as a warning system for attacks by bats.

Structure of the Ear
The ear in humans and most other mammals consist of three parts; the outer, middle, and inner portions. The outer ear, or pinna, is the structure commonly called the ear. It is a skin covered flap of elastic cartilage projecting from the side of the head and funneling sound into the middle ear. The middle ear is an air filled chamber containing the eardrum, or tympanic membrane, and connected to the pharynx by the Eustachian tube, thus equalizing the pressure on the two sides of the eardrum. The inner ear contains the sensory receptors for hearing; these receptors are in a fluid filled chamber called the cochlea. The middle and outer ears serve only to receive and amplify sound waves and occurs only in amphibians and mammals, whereas the inner ear is present in all vertebrates.

In fish, the inner ear is primarily an organ of equilibrium and lacks a cochlea; nor do fish have outer or middle ears. Amphibians posses a middle ear cavity; a thin membrane separating the middle ear from the outside becomes the eardrum. The pinna occurs only in mammals. In birds and reptiles, the eardrum may be in a depression below the surface of the head.

Comments

Post a Comment

Popular posts from this blog

Human Organs

Image
The human organs is drawn such as on the picture belows: Each organ have certain function to our body, if there is a disturbance to certain organ function the body will feel inconvenience and actually the nerve will give an alarm through the network and will sent to the brain. Our brain than should think about what the abnormal condition, and should have any solution to maintain an abnormal situation.
Read more

Nose

The nose, the site of the sense of smell is the organ through which mammals take in air. It is supported by cartilage and bone, covered with skin , lined with a mucous membrane, and provided with muscle. A nasal septum divides it into passages, each of which begins with a vestibule and contains a respiratory and olfactory region. The lining of the vestibule is continuous with the skin and contains hairs, sweat glands, and sebaceous (oil producing) glands . The respiratory region includes nearly all of the septum and the lateral walls of the nose. Goblet cells, which produce and secrete a watery mucus, are present in the lining, as is a type of erective tissue, composed of large, thin-walled veins whose blood supply serves to warm incoming air. The olfactory region is located on the superior concha and adjacent septum. Olfactory cells are present in its lining and have delicate, slender process (modified cilia) at their free surface. Odors from chemicals in the air are received by
Read more

Nervous System on Sole of Foot

Image
The palms of the hands and the soles of the feet have some sweat glands than any other part of body. Excessive hand sweating is the most common sweating problem, sweaty hands usually come along with sweaty feet. When sweaty hands and feet become a severe problem, they are called palmar hyperhidrosis and pedal hyperhidrosis respectively. This tend happen begin in early childhood and become worse after teenage years and early adulthood. The sweaty hands and feet are likely to develop cracking and scaling of the skin, blister, frostbite , warts and fungal infections . According to traditional Chinese medicine, the spleen system controls the muscles and the limbs, the four extremities must be nourished by the nutrient essence transformed and transported by the spleen. Several nervous system on the sole of foot as on the picture below:
Read more

Muscle

Muscle tissue, which comprises about 40 percent of human body weight, consist of threads, or muscle fibers, supported by connective tissue. All living cells can move to some degree, but this ability is highly developed in muscles, which act by fiber contraction; the fibers can shorten to two thirds of their resting length. Muscle vary greatly in structure and function in different organs and animals. Based on structure there are two types of muscles; smooth and s treated, "Involuntary", or smooth, muscles are found in the walls of all the hollow organs and tubes of the body (for example, blood vessels and intestines). There react slowly to stimuli from the autonomic nervous system. The "voluntary," or striated, muscles of the body attach mostly to the bones to move the skeleton, and under the microscope their fibers have a cross striped appearance. Striated muscle is capable of fast contractions. The heart wall is made up of special muscle fibers (cardiac muscle),
Read more