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Biology of Aging Exam 3
Terms and concepts
56
Biology
Undergraduate 3
11/05/2007

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Term
Describe some effects of sensory aging:
Definition

1. Touch, pain, temperature, smell, taste, sight, hearing.  Affecting injury frequency, comfort, appetite.

 

2. Blood Pressure, throat feeling, thirst, bladder and colin fullness.  Affecting VO2 max, aspiration, hydration, incontinence.

 

3. Slight reflex slowing (mylen degradation, neuromuscular synapse failures)  Affecting driving, reaction to imbalance.

 

4. Slight problems with Coordination (potentially serious results) 

Term
Describe aging in the brain:
Definition

-10% loss in total brain size over life span due to some brain cell death and cell shrinkage 

 

-Mostly in frontal and temporal regions there is some neural regeneration that can occur. 

Term
Describe aging in regards to memory:
Definition

-Significant decline in short-term memory.

 

-Mental activity or mental exercises can  help maintain function.

 

-Exercise helps maintain brain function 

Term
Describe aging with regards to depression:
Definition

-Frequency increases with age. 

 

-Although there are chemical changes.  Most probable cause of the increase is due to decreased faculties, other disorders, or social changes.  

Term
What is a stroke and multi-infarct dementia?
Definition

- an occlusion of small or large blood vessels in brain or Hemorrhagic Stroke (vessel rupture and bleeding)

 

- Stroke is the 3rd leading cause of death in USA.

 

- If survived it usually leads to impairment of mental and/or physical function.  Sometimes forewarned by transient ischemic attack 

Term
Transient Ischemic Attack (TIA):
Definition
Miny stroke.  Usually go on blood thinners because you are very vulnerable to a major stroke.
Term
How many new cases of brain cancer are there per year? how many of these are fatal?
Definition
20,000 new cases, 2/3 fatal
Term
What happens when we age with regards to neurons?
Definition

-dendrite branching in cerebral cortex decreases with aging

 

-reduction in neurotransmitter production

 

-the ability to make new synapses (part of memory) diminishes with age (partial restoration by undifferentiated brain tissue transplant, stem cells)

 

-Neuronal cell bodies can harbor viral infection for many years (herpes, shingles, cold sores) 

Term
What are neurofibrillary tangles?
Definition
twisted neurofilaments formed by hyperphosphorylation(adding phosphates onto a protein molecule) of a microtubule-associated protein known as tau, causing it to aggregate in an insoluble form.
Term
What are neuritic plaques?
Definition

- masses of extracellular material with high levels of beta-amyloid protein.

 

- result of mis-processed proteins, a role of free radicals. 

Term
What is the most common form of Senile Dementia?
Definition

Alzheimer's Disease

 

Term
Alzheimer's Disease diagnosis:
Definition

- Psychological impairment of orientation, memory, concentration, symbolic skill: calculation, abstraction, comprehension, ability to work, relate to family/peers, function socially. 

 

- Slowly progressive (probably mostly an oxidative damage disease).

 

- Neurofibrillary tangles and Neurtitic plaques

 

- loss of dendrites, reduction in neurotransmitter production (acetylcholine, dopamine?) 

Term
Treatment for Alzheimer's Disease?
Definition
drugs to increase acetylcholine.  Vitamin C and E combination may help immunization on the way, stem cells.
Term
What is senile dementia?
Definition
the loss of mental function in the aged (mostly over 75)
Term
Alzheimer's Disease occurs in __% of people over 65 and __% of people over 85.
Definition
15%, 50%
Term
Describe Parkinson's Disease:
Definition

- unknown cause.  inflammatory disease - free radicals kill cells that produce dopamine (in charge of smooth muscle action).

 

- Degeneration and loss of neurons in part of the midbrain (free radicals).

 

- Characterized by slow movement, postural tremor and muscular rigidity disturbances in speech, swallowing, strengh.

 

- Surgery, electrical stimulator implants, embryonic stem cells have shown promise. 

Term
Light enters the eye through the ______ through a hole called the _____ in a diaphragm called the ____.
Definition
cornea, pupil, iris.
Term
The light is focused by the ______.
Definition
cornea.
Term
The ____ is where the light is refracted throught the eye fluid (humor).
Definition
lens.
Term
The light sensors of the eye for light is the ____ and for the color is the _____ which are located in the ______.
Definition
rods, cones, retina
Term
The rods and cones relay and electrical signal through the _____ _____ to the brain for interpreation.
Definition
optic nerve
Term
Function of the macula?
Definition
focusing; high detail.
Term
In aging of the eye, what happens to the rods and cones?
Definition
The cones shorten or are lost which means you can't see color as well; the rods lengthen and bend which causes a distortion in the signal that is sent to the brain.
Term
In aging of the eye, what happens to the iris?
Definition
there is decreased elasticity of the iris which means less light is entering the eye and it makes things look darker.  The reaction time of the iris changes as well.
Term
__ _____ causes lens yellowing.
Definition
UV light
Term
What happens when you get a cataract?
Definition
there are chemical changes in the lens which causes cloudiness and limited visual acuity.
Term
In aging of the eye, what happens to the lens?  
Definition
there is a decreased elasticity of the lens which means poorer near vision.  The lens can be replaced with a man-made lens
Term
How does retinal degeneration occur?
Definition
the flow of vitreous humor out of the eye can become blocked leading to increased eye pressure, which can slow blood flow to the retina.  This will also leave dark spots in the field of view.
Term
smoking is a major risk factor for _______ ____________.
Definition
macular degeneration
Term
Sound (air vibration) is channeled by the ________ ___ into the ___ _____ and vibrates the ___ ____.
Definition
external ear, ear canal, ear drum
Term
Vibration of the ear drum vibrates a seris of tiny bones in the middle ear called ________. The three bones here are the _______, the _____, and the ______.
Definition
ossicles, malleus, incus, stapes
Term
The ossicles vibrating initiates pulse waves that stimulate ________________ associated with hair cells in the _______.
Definition
mechanoreceptors, cochlea
Term
mechanoreceptors convert the mechanical impulse into an __________ _______ that is transmitted via the _________-________ _____ to the brain where it is interpreted.
Definition
electrical impulses, vestibulo-cochlear nerve
Term
What is the function of the Eustachian tube?
Definition
to equilize the pressure between the middle ear and the atmosphere.
Term
What is the function of the semicircular canals?
Definition
provide orientation input through the vestibular nerve.  helps you sense movement and position of fluid.  No hearing happens here; you can sense motion in 3-D.  As fluid moves, the nerve moves. 
Term
What is the function of the organ of corti? 
Definition
specialized structures that respond to fluid-borne vibrations in the cochlea with a shearing vector in the hairs of some cochlear hair cells. The Organ of Corti contains between 15,000-20,000 auditory nerve receptors. Each receptor has its own hair cell.
Term
decreased ability to hear is also know as ___________.
Definition
presbycusis
Term
When aging, decreased ability to hear affects about __% of those over 75 years old.  More in men or women and why?
Definition

40%, men becasue men expose themselves to louder sounds throughout their life.  Men are risk takers.  (machines, music, guns). 

 

-Leads to problems responding to stimuli - horns, alarms, phones, words....

 

-May be helped by hearing aids, cochlear implants (sometimes) 

Term
What are some other things that happen to your hearing when you age?
Definition

-loss of spatial orientation which causes dizziness (many meds lead to dizziness).

 

-ear drum gets thicker and less sensitive due to cells repairing damaged parts all the time which reduces your hearing. 

 

-loss of hair cells in part of the cochlea that receives high pitch

 

-loss of neurons and transfer of inputs to brain.

 

-impairment in speech processing (not helped by hearing aids)

 

-ear wax gets stickier and can plug ears easier. 

Term
What is tinnitus?
Definition
perception of sounds not present (ringing, etc.) - several causes - obstructions, infections, neural dysfunction.
Term
As you get older, you loose hearing in high/low frequency sounds?
Definition
high
Term
Functions of the muscle system:
Definition
MOVEMENT - moving organism parts (locomotion and manipulation), moving substances from place to place (swallowing through fecal expelling, blood pumping, gland excretion, breathing, birthing), structural integrity, hair raising, eye movement, body language, vocal language, etc.
Term
Muscles ________ contract to cause movement the _________ extend to return to resting position.
Definition
actively, passively
Term
Muscles are made of multiple ______ ______ (cells) that are made up of varying numbers of __________ which are in turn made up of multiple ____________.
Definition
muscle fibers, myofibrils, myofilaments
Term
Muscles are connected (anchored) to the bones through _______ made of ________.
Definition
tendons, collagen
Term
What is the sarcolemma and what is its function?
Definition
a plasma membrane of a muscle cell designed to spread impulses through the cell by way of the T-tubules to the sarcoplasmic reticulum.
Term
T-tubules?
Definition
invagination of the sarcolemma which effectively brings the extracellular environment in proximity to the innermost confines of the cell.
Term
Sarcoplasmic reticulum?
Definition
specialized endoplasmic reticulum which stores and pumps calcium ions.
Term
Explain the process of a contracting muscle:
Definition

1.  Contraction is initiated by the release and biding of a neurotransmitter to the sarcolemma. 

 

2.  The Sarcolemma spreads the impulses through the cell via the T-tubules to the sarcoplasmic reticulum. 

 

3.  The Sarcoplasmic Reticulum releases calcium to the myofibrils activating ATP breakdown and muscle contraction.

Term
Muscle contractoin relies on what?
Definition
calcium
Term
Myofilaments are made of either _____ (thin) or ______ (thick) in alternating arrays
Definition
actin, myosin
Term
When aging, what happens to the activation of muscles?
Definition
activation of muscles is impaired due to defects in fine structure of neurons and sarcolemma.  This leads to discoordination and therefore weaker response.  Muscle enervation is reduced - leading to the death of the muscle cell.
Term
What is the largest component in muscle thinning?
Definition
death of muscle cells
Term
What is sarcopenia?
Definition
the loss of strength is slow in those that use muscles, fast in those that do not.  Diet must contain sufficient protein to maintain muscle mass.  Indirect causes - illness, medication, joint pain.
Term
A couple other things that happen to your muscles when you age?
Definition

-Muscle circulation is reduced which leads to more anaerobic use and muscle damage.

 

-Usually a decrease in cellular ATP, Sarcomeres, Mitochondria, overall cell thickness.  usually changes in these is a result of inactivity 

 

-Significant hormonal changes affect the ability to make and maintain muscle insulin-like growth factor gene which is a gene that increases muscle mass.  Growth hormone, testosterone, DHEA help incrase muscle mass but with a cost .

 

-Your reaction time increases, but your speed of movement decreases. 

Term
What is glaucoma?
Definition
optic nerve damage from pressure blocking blood supply - diabetes.
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