Ear Anatomy And Physiology With Some Common Disease

Anatomy and physiology of the ear

The human ear is divided into three parts, namely the outer, middle, and inner ear. The outer ear consists of the pinna and the external auditory meatus.

Vital Parts Of the Human Body 

  • Tensortympanic Utriculus
  • Semicircular Canals
  • Incus
  • Muscle
  • Malleus
  • State's
  • Sacculus
  • Ampulla Auditory nerve
  • Pinna
  • Cochlea
  • Tympanic Eustachian
  • Membrane
  • Fenestra ovalis
  • External tubers pharynx (oval window) auditory meats
  • Stapedius
  • Fenestra rotunda muscle (Round window)
  • The mammalian ear structure

The middle ear is made up of the eardrum also called the Atyr. panum, and a chain of three bones connected and called the ossicles. These three ossicles are the malleus, incus and stapes. They are also called the hammer, anvil, and stirrup. 

The bones a are at a right angle to each other ciliano

The middle ear is connected to the pharynx by the eustachian tube. Through this connection, the pressure in the middle ear is equalized with that of the atmosphere.

The inner ear is made up of two very important structures - three loop canals called the semicircular canal with utriculus and sacculus; and a snail shell-shaped canal called the Cochlea. 

These structures are called the membranous labyrinth and are surrounded by fluid called perilymph. The semi-circular canals and cochlea have their inside filled with another fluid called the endolymph

MECHANISM OF HEARING

A sound wave is directed into the ear by the pinna. As the vibrating the sound hit the tympanic membrane there is further vibration. This is then transmitted to the ossicle. 

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The ossicles act as a lever and magnify the sound wave at the end of the stapes. The stapes vibrate against the oral window, and thus set up a vibration in the perilymph. This then pass to the cochlea.

The vibration is therefore passed to the endolymph and from here to the organ of Corti. From the organ of the Corti, nervous impulses are passed through the auditory nerve to the brain.

The brain interprets it and sends it back to the ear and hearing is effected.

FUNCTIONS OF THE EAR

  • Hearing as already discussed.
  • Balance: The semicircular canals are sensitive to changes in the the direction of movement. 
The sacculus and utriculus are sensitive to changes in the position of the head.

SIGNS AND SYMPTOMS OF EAR DISEASE

  1. Earache
  2. Vertigo
  3. Discharge
  4. Deafness
  5. Tinnitus.

CAUSES OF EARACHE

There are Otogenic and non-otogenic Causes: Otogenic causes are as follows:

  1. Wax.
  2. Otitis Media.
  3. Boil.
  4. Eustachian Tube Obstruction.

  •  Non-Otogeni Causes:

  1. Sinusitis.
  2. Tonsilitis. 
  3. AURIS UTempora-Mandibular Joint (TMJ)
  4. Carious Molar Tooth
  5. Cancer of the Tongue.

WAX

This is a thick oily fluid in the ear. It may be soft or hard. Soft wax removed with a probe covered by cotton wool (cotton board). Hard wax is removed using a 10% solution of soap in water.

FOREIGN BODY IN THE EAR

Except for organic foreign bodies, all other foreign bodies are removed by syringing. An organic foreign body such as peanut during syringing making it difficult for it to come out.

SUPPURATIVE OTITIS MEDIA

This may be acute or chronic. In this condition, the large ai containing space of the ear lined with mucous membrane i inflamed.

CAUSES:-

  1. May result from secondary disease of the nasopharynx.
  2. Inflamed adenoid. 
  3. Mucopus from a sinus.

The predisposing factor especially in children is measles.

The organisms commonly implicated are staphylococcus, streptococcus and pneumococcus.

CLINICAL FEATURES

  • EarAche.
  • Malaria and fever in the early stage.
  • Suppurative discharge. (d) Deafness when chronic,

INVESTIGATION

Ear swab for microscopy, culture, and sensitivity.

TREATMENT

  1. Analgesics. 
  2. Eardrop.
  3. Antibiotics based on the laboratory report.
  4. Aural toilet.

If fails to resolve, then the patient is referred to the Ear, Nose, and Throat (ENT) department for expert management.

In the ENT department, further treatment include myringotomy and Grommet insertion.

COMPLICATIONS

  1. Failure to resolve. 
  2. Rapid recurrence after treatment 
  3. Deafness which may be temporary or permanent. 
  4. Spread to other structures such as Mastoid, Facial Nerve, Sinus and the Cranium.

THE HUMAN SKELETON

  • Skull
  • Nose cavity
  • Eye socket
  • Mandible (lower jaw)
  • Maxilla
  • Cervical (upper Jaw) (vertebrae)
  • Pectoral or Cervical shoulder (collar-bone) girdle
  • Sternum
  • Clavicle (shoulder-ribs blade) Humerus
  • Thoracic
  • Forum
  • Vertebrae
  • Lumbar
  • Ulno
  • Vertebrae
  • Radius
  • Pelvic
  • Carpals or hip (wrist) girdle
  • Metacarpals
  • Phalanges (hand bones) (finger Bones)
  • Femur
  • Patella (kneecap)
  • Tarsals (ankle)
  • It is
  • Fibula
  • Phalanges (toe bones)
  • Metatarsal (foot bones)
Human skeleton framework Mammals including human beings have an end toskeleton as against exoskeleton found in insects.
 It is a framework of the body that
supports and protects the soft tissue and organs.

The endoskeleton of man is divided into two parts - the Axial Skeleton and the Appendicular Skeleton

AXIAL SKELETON

This consists of the skull, vertebral column
the ribs and the sternum.
The skull encloses the brain and gives shape to the head. It has many bones fused by joints called Sutures. 
The skull has three main parts -the cranium; the facial skeleton which supports the
nose, eyes and the cheek, and the jaws or mandible.

The vertebral column or backbone protects the spinal cord. It is a disjointed bone. Each bone is held to the other by a ligament called
intervertebral disc.

Different types of vertebrae

  • Cervical Vertebrae:- These are the seven bones of the neck.
The first two of these bones are called atlas and axis respectively
and they carry the skull and assist in nodding and rotation of the
head.

  • Thoracic Vertebrae:- These are the twelve bones of the thorax Or chest.
 The ribs are articulated to them, the back and shoulder
muscles are attached to their neural spine.

  • Lumbar Vertebrae:- These are the five bones of the upper
abdominal muscles. The bone bears the considerable weight of the body.

  • Sacrae Vertebrae:- These are the five bones of the lower abdomen.

  • Caudal Vertebrae:- These are the four bones of the tail. 
They give support to the tail as well as muscle attachment. The ribs are rod-like semi-circular bones that connect the thoracic
vertebrae to the sternum. 

There are twelve ribs in man.

  • Appendicular skeleton:- This consists of the limbs and limb girdles
The limbs are divided into the forelimb and the hind limb. The forelimb is made up of the humerus, the radius and ulnar; the wrist
bones, the carpals, and the metacarpals. 

The head of the humerus articulates with the scapular at the glenoid process.

The hind limb is made up of the femur, the tibia, and fibula, the tarsals
and metatarsals.

The head of the femur articulates with the pelvis at the acetabulum The limb girdles are made up of the pectoral girdle and the pelvic
girdle.

The pectoral girdles consist of two separate bones which are the scapula and the clavicle.
The pelvic girdle consists of three bones that are fused.

These bones are the ilium, the pubis, and the ischium.

FUNCTIONS OF THE SKELETON

  1. It protects the soft tissues and organs.
  2. The skeleton provides a framework from which internal organs are suspended.
  3. It provides a point of attachment to muscles.
  4. It gives the body its shape and form.
  5. The bones of the skeleton manufacture blood cells.
  6. The movement of some parts of the skeleton especially the rib And some muscles facilitate respiration

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