UNIT TEST 3 (Blood, Senses, & Endocrine)

Stimuli

anything that induces response of anorganis’s system.

Senses

ways in which brain receives informtion about the environment and the body.

Sensation

process initiated by stimulating sensory receptors.

Perception

conscious awareness of those stimuli.

General sense and Special Sense

two types of senses:

General Senses

have receptors all over the body.

Somatic and Visceral Sense

two types of general sense:

Special Sense

more specific and localized to a certain structure

Smell, Taste, Vision, Hearing, and Balance

five type of special senses:

Sensory Receptors

sensory have nerve endings or specialized cells that responds to stimuli by developing action potentials.

Mechanoreceptors

respond to mechanical stimuli, such as the bending or stretching of receptors.

Thermoreceptors

respond to temperature changes.

Chemoreceptors

respond to chemicals.

Nocireceptors (noceo means to injure)

responds to stimuli that result in the sensation of pain.

touch, pressure, pain, temperature, vibration, itch, and propioception

7 types of general senses:

Propioception

• sense of movement; and position of the body nd limb.

• important in our ability to maintain posture nd perform various movements

Free nerve endings (simplest

pain, temperature, itch, or movement

skin, tendons, ligaments, muscles

sensory receptors location:

Merkel disks

light touch, and superficial pressure

Hair follicle receptors

light touch, very sensitive

Meissner corpuscles

fine, discriminative touch

Ruffini corpuscles

continuous pressure in skin, deeper tactile receptors

Pacinian corpuscles

deepest receptors, associated with joints and tendons; deep pressure, vibration and body position

Pain

1. Localized, sharp, prickling, or cutting pain, resulting from rapidly conducted action potentials OR

2. Diffuse, burning, or aching pain resulting from

Superficial pain sensations

highly localized due to pain and tactile receptors

Deep, visceral pain (diffuse pain)

not highly localized due to absence of tactile receptors in deep structures

Reffered pain

sensed when deeper structures, such as internal organs, are damaged or inflamed

Propioception

• - "body awareness" - sense that lets us perceive the location and movements of our body parts

• Through specialized sense organs (proprioceptors) located within the muscles and tendons

• The reason we're able to move freely without consciously thinking about our environment.

alam mo na ‘yan

Olfaction

• Bind to receptor molecules on the membranes of the specialized cilia of the olfactory neurons

• Initiates action potentials

• Action potential conducted by sensory neurons to the olfactory cortex (brain) of the cerebrum

Olfactory neurons

• Bipolar neurons in the olfactory epithelium lining the nasal cavity from the olfactory nerves

Olfactory bulb

Where olfactory neurons meet the interneurons that relay action potentials to the brain through olfactory tract

Olfactory tract 

• terminates in the brain (olfactory cortex)

Taste buds 

• contains taste cells with hairs that extend into taste pores.

• Receptors on the hairs detect dissolved substances

• There are five basic types of taste: sour, salty, bitter, sweet, and umami (savory).

Taste

• All taste buds are able to detect all five of the basic taste sensations, each taste bud is usually most sensitive to one class of taste stimuli

• Many taste sensations are strongly influenced by olfactory sensations

• Sense of smell is used to distinguish the difference between sweet and bitter. Sense of smell and taste work together to create the perception of flavor. A person's perception of flavor is reduced if he or she has congested nasal passages.

Facial nerve

• carries taste from the anterior two-thirds of the tongue

Glossopharyngeal nerve

• carries taste from the posterior one-third of the tongue; 

Vagus nerve

• carries taste from the root of the tongue.

Anosmia

loss of sense of smell

Ageusia

loss of sense of taste

A. PHOTORECEPTOR

B. MECHANORECEPTOR

C. CHEMORECEPTOR

What type of sensory receptors are present in the nose and tongue?

Visual system

eyes, accessory structure, and sensory neurons

Visual input

includes information about light and dark, movement and color.

◦ begins as action potentials originating in the eyes and move along the visual pathways and convey visual information to the brain

eyebrow, eyelid

_______ and _______ protects the eyes

Lacrimal apparatus

lubricates eyes through tears

Conjunctiva

thin, transparent mucous membrane covering the inner surface of the eyelids and the anterior surface of the eyes; secretions lubricate the eyes

Fibrous tunic (outer)

contains sclera and cornea

Vascular tunic (middle)

contains choroid, ciliary body, iris, pupil and lens

nervous tunic (inner)

contains retina

Sclera

firm, white, outer connective tissue layer helps maintain the shape of the eye, 

protects the internal structures, and provides attachment sites for the extrinsic eye muscles

Cornea

transparent layer in anterior sixth of the eye permits light to enter, part of the focusing system of the eye, the cornea also bends, or refracts, the entering light

Choroid

POSTERIOR; very thin structure consists if a vascular network and many pigment cells

Ciliary body

ANTERIOR; contains smooth muscles which 

attach to lens

Iris

colored part of the eye, anterior to lens, consists of smooth muscles surrounding pupil to regulate the size of the pupil to regulate amount of light entering

Pupil

center of the iris where light passes through

Pupillary Light Reflex

• allows the eye to adjust the amount of light reaching the retina and protects the photoreceptors from bright light

• Size of the pupil is controlled by the muscles in the iris, causing dilation (dim light/dark) and constriction (bright light)

Lens

clear part of the eye just behind the iris, helps in focusing light and images on the retina

Pigmented retina

keeps light from reflecting back into the eye (absorbs light)

Sensory retina

contains photoreceptors cells as well as numerous interneurons

Photoreceptors

rods (dim light) and cones (color vision)

Macula and fovea centralis

• central and straight vision

optic disc

blind spot of the eye

Macula

high resolution color vision

Fovea centralis

center of the macula, contains only cone cells; where light is most focused; region with the greatest ability to discriminate fine images and help with straight central vision (sharpest vision)

Aqueous humor

• Fills the anterior and posterior chamber

• Helps maintain pressure within the eye

• Refracts the light, and provides nutrients to the inner surface of the eye

Vitreous humor

• Fills the vitreous chambers

• Helps maintain pressure within the eye

Snellen chart

used to measure visual acuity (clarity or sharpness of vision)

Auricle

Fleshy part of the external ear on the outside of the head

Collects sound waves abd directs them toward

Tympanic membrane

(eardrum)

thin membrane that separates the external ear from the middle ear

Vibrates when sound waves are transmitted from ear canal

Ceruminous glands Hair

• Produce earwax (cerumen)

• Hairs and cerumen help prevent foreign objects from

reaching the delicate tympanic membrane

Auditory ossicles (ear bones):

• Malleus (hammer)

• Incus (anvil)

• Stapes (stirrup)

Small bones that form a bony bridge

Transmit vibrations from  tympanic membrane to oval  window

Oval and round window

Connect middle ear to inner ear

Auditory/eustachian tube

Tube that opens to pharynx

Equalize pressure between  outside air and middle ear cavity

Airplane ear

(ear barotrauma)

Bony labyrinth

interconnecting tunnels and chambers within the  temporal bone, inside is membranous labyrinth, smaller set of membranous tunnels and chambers and filled with fluid (endolymph)

Cochlea

 involved in hearing; has spiral organ (organ of Corti) that 

contains sensory cells (hair cells)

Vestibule

involved in balance

Semicircular canals

involved in balance

Static equilibrium

• linear motion; associated with the vestibule and is involved in evaluating the position of the head relative to gravity

Dynamic equilibrium

rotational motion; associated with semicircular evaluating changes in the direction and rate of head movements

utricle and saccule

Vestibule - has 2 chambers:

utricle macula

it is the horizontal chamber of vestibule

saccule macula

the vertical chamber of vestibule

ampulla

• base of each semicircular canal

crista ampullaris

• epithelium within each ampulla

Cupula

• curved, gelatinous mass in the (like macula in vestibule)

PRESBYOPIA

most common age-related change in the eyes

• lens loses flexibility that affects accommodation

  • number of cones decreases, especially in the fovea centralis → gradual decline in visual acuity and color perception.

PRESBYCUSIS

number of hair cells in the cochlea decreases, resulting in age-related sensorineural hearing loss

MYOPIA (nearsightedness)

ability to see close but not distant objects; caused when refractive power of cornea and lens is too great relative to length of eye

HYPEROPIA (far-sightedness)

ability to see distant but not close objects; caused when cornea is too flat of lens has too little refractive

ASTIGMATISM

• Cornea or lens is not uniformly curved, so image is not sharply focused

CATARACT

Clouding of lens (clumping of proteins) as a result of advancing age,

infection, or trauma; most common cause of blindness in the world

DIABETIC RETINOPATHY

Involves optic nerve degeneration, cataracts, retinal detachment; often caused by blood vessel degeneration and hemorrhage

Glaucoma

group of eye diseases that can cause vision loss and blindness 

by damaging optic nerve

• usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve.

NIGHT BLINDNESS 

characterized by difficulty seeing in DIM light; usually common among people with Vitamin A deficiency

An insufficient amount of vitamin A in the body affects the production of rhodopsin, the necessary pigment for night vision (rods)

COLOR BLINDNESS

color vision deficiency, makes it hard to tell the difference between certain colors

• The difference between colors

• How bright colors are

• Different shades of colors

TINNITUS

Phantom sound sensations, such as ringing in ears; common problem

Causes: noise exposure, medications, earwax or ear infection, head or neck injuries

MENIERE'S DISEASE

Vertigo, hearing loss, tinnitus, and a feeling of fullness in the affected ear; most common disease involving dizziness from inner ear; cause unknown but may involve a fluid abnormality in ears

Endocrine System

• regulates body activities by releasing hormones (chemical messengers) into the bloodstream, where they are carried throughout the entire body

Autocrine

Secreted by cells in a local area; influences the activity of the same cell or cell type from which it was secreted

Eicosanoids (prostaglandins, thromboxanes, prostacyclins, leukotrienes)