Anatomy chapter 11 (The senses)

How smell works

1: incoming odor molecules bind to cilia projecting from the ends of the olfactory receptor cells 2: this stimulates and impulse along nerve fibers leaving the nasal cavity through pores of the ethmoid bone. 3: the fibers synapse with other neurons in olfactory bulbs, a pair of structures residing just underneath the brains frontal lobe. intermediate neurons called glomeruli partially process the impulses. 4: the signals continue on to the primary olfactory cortex in the brain

How many taste buds do a child have?

A child has 10,000 taste buds. The number declines with age, and elderly people have fewer than 5000 taste buds

What are drugs used to relieve pain called?

Drugs used to relieve pain are called analgesics

What are he two types of pain receptors?

Fast pain fibers: a lot in the skin and the mucous membrane. Produces a sharp, localized, stabbing type pain at the time of injury. Ex: when you stub your toe or slam you hand between the door Slow pain fibers: these are congregated in deep body organs and structures. Produces a dull aching pain Ex: pain from a bowel obstruction or appendicitis

Temperature

Free nerve endings called thermoreceptors mediate sensations of heat and cold. Warm receptors: Located in the dermis Activated above 77*F or 25*C Beyond about 118*F a sensation of burning begins Cold receptors: Located deep in the epidermis Activated between 50*F and 104*F Below 50*F, firing of the cold receptors decreases and the temperature acts an anesthetic before activating pain receptors; triggering the feeling of freezing pain.

Smell

Lining the roof of the nasal cavity is a small area of epithelium that contains receptors cells for olfactory(Sense of smell) the receptors cells-which are essentially neurons-leave the nasal cavity through pores in the ethmiod bone; they then gather together to form cranial nerve 1(The olfactory nerve).

Pain

Nociceptors or pain receptors, consist of free nerve endings that carry impulses to the brain. There is a lot in the skin and mucous membranes and found in almost every organ except the brain.

What is referred pain?

Pain originating from a deep organ my be sensed as if its origami get from the body's surface- sometimes at a totally different part of the body This occurs because sensory fibers from an organ and those from an area of skin converge in a single pathway. ***look at page 208

Where do taste buds reside?

Taste buds reside along and between the papillae The taste buds look similar to an orange, which each segment containing 25-50 chemoreceptors called gustatory cells or taste cells

Taste

Taste(Gustation) results when chemicals come in contact with taste buds. Most taste buds are located around protrusions on the tongue called papillae, although a few reside in the lining of the mouth and soft palate.

what are the three smallest bones in the body?

The Auditory ossicles they are named for their shape: Malleus (Hammer) Incus (Anvil) Stapes (Stirrup) the stapes fits within the oval window of the vestibule, which is where the inner ear begins

What are the 4 primary tastes?

The four primary tastes are salty, sweet, sour, and bitter.

What does the inner ear consists of?

The inner ear is called the bony labyrinth because of its complicated pathways

The special senses Page 209

The special senses, which include taste, smell, hearing, equilibrium, and vision- involve receptors that are either grouped together or clustered in specialized organs

How do sensory receptors work?

a sensation begins when a receptor detects a stimulus 2:if the stimulus is strong enough, the receptor causes a sensory neuron to send an impulse to the brain and the spinal cord. 3: when the impulse arrives at the brain, we may experience a sensation, such as a sight or sound.

What is ear wax?

ear wax is secretions from the canal plus dead skin cells this is also called cerumen cerumen waterproofs the canal and traps dirt and bacteria the cerumen normally dries and the propelled by jaw movements during eating and talking, works it ways out of the ear.

The tongue contained 4 types of papillae

1: vallate papillae A large papillae found at the rear of the tongue; although few in number, they contain up to half of all taste buds 2: foliate papillae Form ridges at the sides of the tongue 3: Filform papillae Are thread like papillae that contain no taste buds; hey play a role in helping us distinguish the texture of food 4: fungiform papillae: Especially concentrated at the tip and sides of the tongue

are we aware of when must our bodies sensory processes take place?

No, most of our body's sensory processes take place without our awareness example: the sensory system is integral (essential) in maintaining such vital functions as blood pressure, body temp., and balance.

What are examples of muscle and tissue that combined with sensory receptors to form sense organs?

The ears, the eyes, and the nose.

Touch

Specialized nerve endings, most of which are mechanireceptors, provide for the senses of touch, pressure, and stretch. Some receptors are enveloped in connective tissue while others are uncovered. These receptors are located of sensitive, hairless, areas of skin like fingertips, palms, eyelids, lips, nipples, and genitals. These receptors have different sizes and shapes The broad variety allows us to feel the difference between a wide range of textures Ex: knowing the difference between fine silk and rough burlap.

Hearing

The ear provide the sense of hearing; their also essential for balance (Equilibrium) the ear has three sections the outer ear, the middle ear, and the inner ear

classification of receptors

receptors are classified by the type of stimuli they detect 1: chemoreceptors these receptors react to various chemicals (Including odors and tastes), as well as the concentration of various chemicals (such as glucose or carbon dioxide) in the body. 2: Mechanoreceptors these receptors respond to factors- such as pressure, stretch, or vibration- that change the position of a receptor. 3: Thermorecpetors there receptors are activated by a change in temperature 4: nociceptors these are pain receptors that respond to tissue damage from trauma as well as from heat, chemicals, pressure, or lack of oxygen. 5: photoreceptors found only in the eyes, these receptors respond to light 6: proprioceptor found in the skeletal muscle, tendons, and joints, they provide information about body movement, muscle stretch and general orientation of the body.

sensory receptors

scatter through out our body, are million sensory receptors. Some of these receptors combine with muscle and tissue to form sense organs most though, are specialized nerve cells or nerve endings that detect physical or chemical events outside the cell membrane.

What do sensory receptors translate information about? three kinds of info obtained by sensory receptors

sensory receptors translate information about the type, the location, and the intensity of each sensation Type: each sensory receptor responds to a different stimulus ex: cold receptors respond only to cold while light receptors respond only to light. this allow the nervous system to differentiate between the various sensations. Location: each sensory neuron responds to stimuli in a certain area, called a receptive field. so when a particular neuron carries a stimulus to the brain, the brain knows where the stimulus came from (Also known as sensory projection). Intensity: the stronger a particular stimulus, the more nerve fibers fire. this allows the brain to interpret the intensity of a sensation

what are the 5 main senses?

sight hearing taste touch smell

What does the middle ear consist of ?

the middle ear consists of these structures: Auditory ossicles: the three smallest bones in the body connect the ear drum to the inner ear

what does the outer ear consists of?

the outer (external) ear, consists of the auricle (or pinna) and the auditory canal the Auricle(Pinna) is the visible part of the ear. shaped by cartilage, this part of the ear funnels sound into the auditory canal The auditory canal: leads through the temporal bone to the eardrum. (The opening of the auditory canal to the outside of the body is called the external acoustic meatus.) glands lining the canal secrete ear wax.

give an example of a location on the body with weak sensory projection and strong sensory projection..

the tip of the finger has a dense population of receptors because each neuron covers a tiny area, the brain can pinpoint the location of the stimulus. the back has less receptors so when you feel something, the brain cant exactly pinpoint where it is from.

What is the tympanic membrane?

this is the eardrum Separates the inner ear from the middle ear vibrates freely in response to sound waves the Auditory or Eustachian tube is a passageway from the middle ear to the nasopharynx. its purpose is to equalize pressure on both sides of the tympanic membrane. unfortunately it also allow infection to spread from the throat to the middle ear