1
Q
What are the 5 special senses?
A
- Taste
- Smell
- Sound
- Sight
- Balance/position detection
2
Q
What is taste?
A
The conceptual response of the brain to signals received from the gustatory cells.
3
Q
How many primary tastes are there?
A
5
4
Q
Where are taste receptors located?
A
In the taste buds
5
Q
Where are the 10000 taste buds found?
A
- Most on the tongue
- Some found:
On the soft palate
Inner surface of the cheeks
Pharynx
Epiglottis
6
Q
What gives the tongue its rough feel?
A
Tastebuds on the tongue are found in papillae, corrugations of the tongue mucosa which give the rough feel
7
Q
What are the three types of cell found in taste buds?
A
- Supporting cells
- Sensory cells
- Basal cells
8
Q
Describe receptive/gustatory (sensory) cells
A
- Have specialised cilia that are bathed in saliva ( these are the ‘sensory’ parts)
- Gustatory cells respond to molecules and sends nerve signals to the brain. The brain processes these signals as taste.
9
Q
Describe supporting cells
A
- Form the bulk of the taste bud
- Surround and support the sensitive gustatory cells
10
Q
Describe basal cells
A
Act as stem cells to produce new supporting cells which in turn produce new gustatory cells
11
Q
What are the 5 taste categories?
A
- Sweet
- Salty
- Sour
- Umami
- Bitter
12
Q
Explain the ‘sweet’ taste
A
Induced by many organic substances including; sugars, alcohols, some amino acids, and some lead salts.
13
Q
Explain the ‘salty’ taste
A
Salty taste is produced by metal ions (inorganic salts) (sodium chloride) tastes the “saltiest”.
14
Q
Explain the ‘sour’ taste
A
Produced by acids, specifically their hydrogen ions (H+) in solution.
15
Q
Explain the ‘bitter’ taste
A
Bitter taste is elicited by alkaloids (such as
quinine, nicotine, caffeine, morphine, and strychnine) as well as a number of non alkaloid substances, such as aspirin.
16
Q
Explain the ‘umami’ taste
A
Elicited by the amino acid glutamate, which appears to be responsible for the “beef taste” of steak, the characteristic tang of ageing cheese, and the flavour of the food additive mono-sodium glutamate.
17
Q
How is a taste receptor activated?
A
- The molecule must dissolve in saliva, diffuse into the taste pore, and contact the gustatory hair receptor. On activation the
receptor cell releases neurotransmitter which will cause a graded potential to sensory nerve.
18
Q
What is the organ of smell?
A
The Olfactory Epithelium,
found in the roof of the nasal cavity.
19
Q
Describe the structure of the olfactory epithelium
A
The olfactory epithelium comprises millions of Olfactory
Receptors. Cells surrounded by supporting cells (which make
up the bulk of the tissue), with basal cells forming the
remainder.
20
Q
What are the two schools of thought as to how odours are detected?
A
a) Up to a 1000 different receptors, each able to bind to a
specific molecule or type of molecule.
b)A few receptors that work in combination (like cone
receptors in the eye that allow us to detect many different
colours).
21
Q
How is an olfactory receptor activated?
A
For an odorant molecule to be detected, it must:
Firstly, it must be volatile ( the gaseous state) as it enters
the nasal cavity.
Secondly, it must dissolve in the mucus layer that coats the
epithelium.
Dissolved odorants stimulate olfactory receptors leading to a
graded potential and an action potential if sufficiently
activated.
Olfactory receptors also adapt quickly. When adapted,
before the smell can be detected again the activating
molecule must be washed away from the receptor and from
the mucus so the receptor can become receptive again. Then
it can be re-exposed.
22
Q
What is sight?
A
The ability to detect light energy.
23
Q
How is the concept of our sense of sight created?
A
The eye is a transducer that converts light energy into nerve signals which are sent to the brain along the optic nerves. The brain processes these signals to create the concept that we call
our sense of sight.
24
Q
The eye and brain describe the environment around us in what three terms?
A
- Shape and form
- Colour
- Movement
25
Describe the role of the eyebrows
Short coarse hair overlies the supraorbital margin of the skull. They help shade eyes from sunlight and prevent perspiration trickling down the forehead from reaching the eyes.
26
Describe the role of the eyelids
Protection from excessive light and foreign objects, spreading of
lubricating secretion over eye ball.
27
Describe the role of the medial commissure (towards the nose)
Contains sebaceous and sweat glands and produce whitish oily secretion (usually collected during sleep)
28
Describe the role of eyelid muscles
Activated to cause blinking every 3-7 seconds (keep eye moist).
29
Describe the conjunctiva
Transparent mucous membrane coving white of the eye ( only the front). It does not cover cornea! The blood vessels you see on the surface of sclera actually belong to conjunctiva. Inflammation of conjunctiva is called conjunctivitis. The conjunctiva is kept moist by tears secreted by the lacrimal gland.
30
What are the three layers of the inner eye structures?
- Sclera
- Choroid
- Retina
31
Describe the sclera
Outer most hard, posterior portion and bulk of the fibrous layer. It is glistening white and opaque. Seen as "white of the eye” Posteriorly, where the sclera is pierced by the optic nerve (CNII).
32
Describe the cornea
The anterior sixth of fibrous layer is modified to form the transparent cornea. Cornea bulges anteriorly from its junction with the sclera.
33
Describe the choroid
Vascular pigmented structure. It has a dense network of tiny blood vessels which nourish all eye layers.
Brown pigment, melanin, helps absorb light and prevents
scattering and reflecting. Towards the front, choroid thickens making ring of tissue called Ciliary body. This region has ciliary muscles (control lens shape), ciliary processes
( secrete the fluid) and the ciliary zonule (suspensory
ligament hold lens).
34
Describe the iris
Iris is the colored part you see
through cornea. It is shaped like flattened doughnut and lies
between the cornea and lens. it has a round central opening
called the pupil (black hole). Some of the fibers of iris are
arranged like spokes in a wheel. When they contract, pupil
dilate (lets more light in ). Some other fibers are circular, if
they contract, the pupil constrict ( lets less light in).
35
Describe the lens
The lens lies directly behind the pupil. It can change shape to
precisely focus light on the retina. It is held in place by a
ligament attached to the Ciliary muscle.
When you look at distance objects, the ciliary muscle is relaxed and the lens a slightly curved shape. However, when you look at near objects, the ciliary muscle contracts and cause the lens to curve even more.
36
What does the retina (inner layer) contain?
1- Millions of photoreceptors that convert light energy
2 - Contains other neurons involved in process responses to
light
3- Glia
37
What are the two types of photoreceptor cells?
RODS – work in low light levels, give black and white
information at low resolution and are found outside of the
fovea ( near by optic disc). The enable you to see in “the
dark”.
CONES - work in daylight conditions, provide high quality
(acuity) vision, found mainly at the fovea, 3 types - red,
green and blue sensitive, these allow you to see the world in
colour.
38
Explain the blind spot
Where the nerves exit the eye (optic nerve head) there are no photoreceptors.
39
Explain the importance of fluids in the eye
- Fill the hollow space inside the eyeball
- Maintain the normal shape of the eyeball
- Help refract light
- The fluid bending the light brings them to focus on the retina
40
What is the aqueous humour?
- Watery clear fluid in front of the lens
- Fills entire anterior segment of the eye
- Forms by ciliary process
- Drains continuously
- Glaucoma = drainage of aqueous humour gets blocked, internal pressure in the eye increases and damages retina
41
What is the vitreous humor?
- Jelly like fluid behind the lens (in the posterior chamber)
- Formed in the embryo and lasts for life
- Transmits light, supports lens, holds neural layer
- Contributes to intraocular pressure
42
What allows the extrinsic eye muscles to be so precise?
High axon to muscle fibre ratio
43
Explain how light travels from the pupil and reaches the visual cortex
- Light enters the eye through the pupil and is refracted so that it is focused on the retina
- Refraction happens as the light passes the cornea, the aqueous humor, the lens and the vitreous humor on its way to the retina.
- Photoreceptors in the retina respond to the light stimulus by producing a nerve impulse
- Nerve impulse leaves the retina and leaves through the optic nerve
- There are no rods or cones in the optic nerve
- After leaving the eye, the optic nerves enter the brain, half of the nerves are crossed over to the other side of the optic chiasma (crossover)
- They continue to the thalamus and reach the visual cortex
44
What is the role of the eye lids?
- Protect the surface of the eye
- Keep it moist and clean
- Reduce light entering the eye
45
What is the role of the cornea?
- Tough transparent window to the eye
46
What is the role of the iris?
An apeture (gap/hole) in the eye that limits the amount of light entering
47
What is the role of the lens?
An adjustable lens that helps focus light onto the retina
48
What is the role of the suspensory ligament (zonules) tendons?
Connect the lens to the ciliary muscle that brings about the shape change of the lens.
49
What is the role of the ciliary body?
The muscular component that controls the shape of the lens, the secretory component produces aqueous humour
50
What is the role of the aqueous humor?
Nourishes the cornea (which has no blood supply).
51
Vitreous humour
Keeps the eyeball inflated.
52
Retina
Converts light energy into electrical signals.
53
Choroid
Nourishes the retina and makes the globe light tight.
54
Sclera
Tough outer coat of the eyeball.
55
Extra-ocular muscles
Move the eyes
56
Lacrimal gland
Produces tears that; keep the front surface of the eye moist (non-keratinised epithelium), have antibacterial actions and lubricate the blink
57
Optic nerve
Carries electrical signals from the eye to the brain.
58
What are the two systems of the ear?
Auditory system - Sound perception- hearing
Vestibular system – Balance or equilibrium
59
What are the two parts of the external ear?
- The auricle (pinna)
- External acoustic canal
60
Describe the structure of the external acoustic canal
- Short, curved tube
- Extended from the auricle to the ear drum (tympanic membrane).
61
Describe the ear canal
Lined with skin bearing hairs, sebaceous glands and ceruminous glands that help to produce cerumen (earwax)
62
What is the role of cerumen (ear wax)?
Helps skin's drying and traps dust that enters the canal
63
The tympatic membrane (eardrum) is the boundary between what?
The outer and middle ear
- It transfers the sound energy to the tiny bones of the middle ear and acts like a satellite dish
- Sometimes infections cause the eardrum to become red and inflamed
64
The middle ear chamber
- Closed at one end by the ear
drum.
- It has an opening to the nasal cavity (nasopharynx) via
the eustachian tube and has 3 tiny bones (malleus-hammer,
incus-anvil, stapes-stirrup) that conduct vibrations of the
tympanic membrane to the inner ear structures.
The stapes presses against a membrane that covers a small opening (oval window). This structure separate the middle ear from the inner ear.
65
The inner ear
- Contains two sensory organs the vestibule and cochlea.
- The vestibule is the organ of balance.
- The cochlea is the organ of hearing.
- Anatomically, the inner ear has
three spaces in the temporal bone, assembling a complex
maze called the bony labyrinth. -- This odd shape bony structure filled with a watery fluid called perilymph and divided into three parts: vestibule, semicircular canal and cochlea.
66
Key structures of the ear
1. Anterior semicircular canal
2. Ampulla (superior canal)
3. Ampulla (lateral canal)
4. Sacculus
5. Cochlear duct
6. Helicotrema
7. Lateral (horizontal) canal
8. Posterior canal
9. Ampulla (posterior canal)
10. Oval window
11. Round window
12. Vestibular duct (scala vestibuli)
13. Tympanic duct (scala tympani)
14. Utricule
67
The cochlea
- Is the spiral shaped organ (transducer) that converts
vibrations (sound waves) into action potentials.
- The tube that forms the spiral has 2 membranes that
effectively divide the tube into 3
compartments :
a)vestibular duct
b)cochlear duct
c)Tympanic duct
- "a" and "c" are filled with perilymph, "b" is filled with
endolymph
68
How is sound detected?
- Sound waves in the air strike the tympanic membrane
causing it to vibrate.
- The malleus which is attached to the tympanic membrane
passes the vibration to the incus and then onto the stapes.
- The stapes is in contact with the oval window and so the
vibrations are transmitted via the oval window to the fluid
within the vestibular duct. This creates a fluid wave within the cochlea.
- The fluid waves cause the basilar membrane of the
cochlear duct to vibrate.
- Sound waves are transmitted to the tympanic duct and
dissipated back into air by the movement of the round
window.
69
The vestibule
- Behind to the cochlea.
- It serves as the the
entrance to the inner ear.
It hosts two membranous sacs; the saccule and utricle which sense gravity changes.
70
Which parts of the ear detect a stationary position?
The utricle and saccule
71
Which parts of the ear detect dynamic movement?
The semi-circular canals.
72
What enables us to detect movement in any direction?
Three fluid filled semi-circular canals set at 90o to each
other
73
What is the main function of the rods?
Vision in dim light
74
The clear central anterior portion of the sclera is called what?
The cornea
75
The 'white of the eye' is known as what?
The sclera
76
The portion of the eye that regulates the amount of light entering the eye, similar to the diaphragm of a camera, is called what?
The iris
77
Where does the chemical reaction associated with vision take place in the eye?
The retina
78
A mucous membrane that lines the inner surface of the eyelid and continues as the surface layer of the sclera is called what?
The conjunctiva
79
What are responsible for day/colour vision?
Cones
80
When a person lacks one of the cone's photopsin pigments, the result is what?
Colour blindness
81
What is a cataract?
A degenerative process with increasing opacity of the lens of the eye, resulting in blurred vision.
82
Why does a diabetic retinopathy patient require immediate treatment?
To prevent permanent visual loss, because the retinal cells are deprived of nutrients.
83
A blockage in the canal of Schlemm might result in what?
Glaucoma
84
What is the most frequent infection of the eye?
Conjunctivitis
Anatomy and Physiology SHC151
flashcards
Decks in class (34)
# Cards
-
Basic Chemistry43
-
Microbiology57
-
Enzymology23
-
Cell metabolism25
-
Introduction to genetic traits45
-
Cell Biology20
-
Protein synthesis and cell division69
-
Special senses84
-
Blood components51
-
Blood groups25
-
Blood clotting42
-
The nervous system part 124
-
The nervous system part 222
-
Histology29
-
Anatomy of the respiratory system38
-
Acid-base balance85
-
The muscle64
-
Homeostasis17
-
The skin29
-
The Digestive System36
-
Excitable cells99
-
The liver33
-
Embryology24
-
Introduction to the renal system70
-
Introduction to organic molecules20
-
Overview of the cardiovascular and cardiac conduction systems65
-
Introduction to immunology23
-
Chemical and cellular events of acute inflammation74
-
Reproductive systems37
-
Physiology of pregnancy10
-
Skeletal system18
-
Physiology of ageing33
-
Revision A+P John28
-
Revision A+P Alex48
