BSC2086L Final

pulse transducer

Wraps around your thumb is used to record your pulse

standard deviation

a measure of variability that describes an average distance of every score from the mean

cell membrane function

Controls the movement of substances into and out of the cell

components of cell membrane

phospholipids, proteins, carbohydrates, cholesterol

saturated fats

fats that are solid at room temperature

unsaturated fats

A fat that is liquid at room temperature

spectrophotometer

An instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution.

We used __ in the biological membranes lab to determine how different solvents can affect membranes

spectrophotometer

Why are beets useful as an experimental organism?

Beets store their pigment in a membrane-bounded vacuole in each cell, so they provide a good model. They also have a very bright color which makes measurement easier.

Which solvent treatment damaged membranes the most? Which one damaged them the least?

the 50% methanol and acetone solvents had the most damaging effects with the water having the least damaging effects.

Temperature's effect on cell membrane

Increased temperature = increased permeability

Solvent's impact on cell membrane

Higher concentration solvents like alcohols cause increased permeability

Phospholipid

glycerol attached to two fatty acids and a phosphate group attached to a choline

Amphipathic

hydrophobic and hydrophilic

Cholesterol

strengthens the cell membrane and maintains fluidity

Membranes with unsaturated lipids can cause ____ in lipid packing making them ____ permeable to small molecules

disruptions, more

The bilayer has weak __-___ bonds

non-covalent

when a bilayer freezes, where will it fracture?

the weakest point

Where are pigments contained in beets

cell vacuoles

Vision detects what type of energy?

electromagnetic

Visible spectrum

380-750 nm

Cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

Rods

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond

optic disc

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

saccadic masking

during rapid movement, the optic nerve ceases to transmit visual information

3 sets of cones

red--->564nm
green--->534NM
Blue---> 420nm

Protanopia

Defect in red cones. Complete red cone deficiency.

Protanomaly

Color blindness due to a partial lack of red cones.

Deutanopia

complete green cone deficiency

deutanomaly

altered sensitivity in the green cone function

Tritanopia

lack of functioning blue cones

Audition (Hearing)

tiny hair fibers in the inner ear detecting motion of the membrane. Ear drum vibrates in response to change in air pressure. Sound can also be detected as vibrations conducted through the body by tactition

2 chemical senses

taste and smell

Gustation (Taste)

five types of taste buds (sweet, salty, sour, bitter, umami). Combination of taste and olfactory receptors, temperature, and sight

Olfaction (smell)

hundreds of olfactory receptors each binding to a particular molecule. All receptors in roof of nasal cavity.

Tactition (touch)

sense of pressure. Several types of specialized tactile receptors in skin, muscles, viscera.

Nociception (pain)

response to stimuli likely to cause tissue damage. Pain is an adaptive interpretation of the stimulus NOT THE STIMULUS ITSELF. Fast Pain vs Slow Pain

fast pain

carried from injured tissue by myelinated A-delta fibers

slow pain

delivered to the CNS by unmyelinated C fibers

Thermoreception (heat)

Above 45 Celsius, pain receptors are activated. At high and low temperatures these receptors DO NOT adapt as a way to prevent temperature related to injury of tissues

homeostatic thermoceptors

provide feedback on internal body temperature

Equilibrioception (Balance)

related to the inner ear. Semicircular canals - fill with endolymph and detect rotary movements of the head, utricle and saccule- detect linear acceleration and gravity. Crista Ampullaris consists of gelatinous wedge shaped structure influenced by the flow of endolymph. Cilia of the receptor cells are embedded in htis gel. When the head moves the gel is distorted and the cilia bend. Rotary movements of the head are detected.

Proprioception (body position)

unconscious awareness of where the various regions of the body are located at any one time

structure of sensory neurons

Unipolar
Cell bodies grouped in sensory ganglia
Processes (afferent fibers) extend from sensory receptors to CNS

adaption of thermoception

occurs when the sensory receptors become exposed to stimuli for a prolonged period. Depending on the stimulus, receptors may increase or decrease their ability to respond, and will develop an enhanced or diminished sensitivity to the stimulus

Anatomy of the eye

Includes conjunctiva, cornea, sclera, choroid, retina, iris, lens, aqueous and vitreous humor, ciliary body, optic nerve

cerebral cortex

outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain

Golgi tendon organs

proprioception

hair cells

hearing

nociceptors

pain

muscle spindles

proprioception

retinal cells

sight

olfactory receptors

smell

thermoreceptors

temperature

mechanoreceptors

touch

Pacinian corpuscles

high frequency vibration

Meissner's corpuscles

low frequency vibration

Convergence Gaze activity

double images

binocular vision

vision using two eyes with overlapping fields of view, allowing good perception of depth.

Positive Afterimage activity

bright features of the scene remain visible for a long period of time

Delta waves

.5-4 hz, the large, slow brain waves associated with deep sleep

Theta waves

4-8 hz, medium sized waves, light sleep

Beta waves

13-30 hz, in awake and alert individuals with their eyes open

alpha waves

8-13 hz, when the eyes are closed and the volunteer is relaxed

Artifacts in EEG

epuipment, patient, and enviroment

What happens to alpha waves when the eyes close vs open?

Closed should have higher frequency than open

EEG is a tool used in the diagnosis of ____ and brain ____

epilepsy, death

brain structure

the physical form and organization of the brain

The stretch reflexes are examples of ____________ reflexes

myotatic

The stretch reflex employs only ____ neurons

2

Explain the patellar reflex

Striking the patellar ligament just below the patella stretches the quadriceps muscle. This stimulates the sensory receptors in the muscle that trigger an impulse in a sensory axon.

The sensory axon cell body lie in the ____ ganglion in the lumbar region of the spinal cord

dorsal root

The sensory axon synapses are directly next to a ___ ___, which conducts the impulse to the quadriceps triggering contraction

motor neuron

flexion withdrawal reflex

withdrawal of a limb from a painful stimulus

Despite the speed of a flexion withdrawal reflex, the reflex involves ____ synaptic links

several

Pain (nociceptive) sensory neurons leads to stimulation of _____ muscles which leads to the withdrawal of the stimulated limb. At the same time, there is an inhibition of _____ muscles in the opposite limb

flexor, extensor

crossed extensor reflex

opposite limb supports body during withdrawal of injured limb

upper motor neuron lesion

increased muscle tone, resistance to movements, muscle weakness, hyperreflexia, Babinski sign

lower motor neuron lesions

paralysis, muscle weakness, spontaneous contractions fo groups of muscle fibers and individual muscle fibers, areflexia, hyporeflexia, hypotonia, atonia, no babinski

Why would there be a lag between the raw data signal and the channel calculation signal that you see on screen?

There is some processing time required to perform a channel calculation (# of beats).

why do you think it would be advisable to record the heart rate for 60 seconds rather than for a shorter duration (for example, 15 or 30 seconds)

The person may have an irregular heartbeat which could be missed if recording for only 15 or 30 seconds.

Why is it important to keep the size and shape of the beet samples the same for each treatment?

You want the surface area for samples to be the dame so that the solvent penetrates equally.

Which solvent treatment damaged membranes the most? Which one damaged them the least? Explain your result.

Higher solvent concentration = more damage. Lower concentration = less damage.

Why is it important to blank the spectrophotometer?

The tube and solvent have a small amount of optical density that must be accounted for.

Provide a detailed explanation of what you saw when you performed the convergence of gaze activity.

I saw double images. So, when I had both fingers up with both eyes open it was a cluster of images, but when I shut one eye I can easily focus and view only one "image" at a time.

Describe your observations regarding the accommodation activity. How does the near point differ between people with normal vision and those who are nearsighted?

Students who are nearsighted should have a significantly shorter near point than those with normal vision.

When you change your focus from a near object to a far object, what occurs in the eye to allow you to focus on the object?

The ciliary muscles control the curvature of the lens by relaxing. Increasing the tension of the suspensory ligaments stretches the lens to a thinner shape.

Describe what you saw during the negative afterimage activity.

after looking at the black pen for an extended period of time, there was a clear white silhouette on the blank white page (that appeared grayed out). However, the red pen had a lesser result and produced a greenish-blue image.

Given the number of blood vessels in the retina, why do you suppose that you are not able to see them normally?

I think this is a function of sensory adaptation. If we were able to see all of the blood vessels then it would probably interfere with our normal vision function, so i would think the brain would block them out.

Describe your observations here. Is our taste sensitivity uniform across the tongue?

Sensitive of taste receptors to different tastes varies with region across the tongue

What happened to the alpha waves when the eyes were closed compared to when they were open?

Alpha waves can be seen during wakeful relaxation when the eyes are closed When the eyes are open the alpha waves are reduced.

What effects did the mental arithmetic have on the alpha wave activity?

Alpha waves are though to indicate a brain that is calm, relaxed, and awake. It would be expected that the alpha amplitude should be significantly reduced and the alpha frequency somewhat depleted by mental effort such as calculations.

How can you explain the change in potential across the hand that follows peripheral nerve stimulation?

Peripheral nerve stimulation is conveyed to the brain, which activates the sympathetic nervous system. This leads to stimulation of sweat production. Why does sweat release cause a change in electrical potential across the hand? The sweat glands on the palm are activated by sympathetic stimulation. However, sweat glands on the dorsal, hairy surfaces of the hand are not activated by sympathetic stimulation. Thus sympathetic nerve activation results in brief potential difference across the hand.

This response can also be seen by measuring the skin potential of the sole of your foot. How would you expect the latencies and amplitudes in the skin of the hand and the foot compare? Explain any differences in the latencies.

Postganglionic sympathetic nerves supply the sweat glands, C fibers. C fibers are unmyelinated with slow conduction velocities. therefore, there is a characteristic latency or delay between stimulus and response. We would expect greater latency in the food response because nerve impulses travel a greater distance to the food. Note that nerve stimulation occurred on the opposite side to the measurements. So, sweat response is not a direct stimulation of nerves supplying the sweat glands.

You may observe a change in the skin potential even before the stimulus is delivered. How can you explain this?

This may be due to anticipation of the tap, a change in sound in the environment that signals that the tap is about to happen.

Describe the volunteer's skin potential response after the startle and gasp stimuli. How can you explain these findings?

Some tissues are only supplied by one division of the ANS. For example, sweat glands are only supplied by the SNS. As would be expected, stressful stimuli activate the SNS and stimulate sweating. The gasp is commonly used to activate the SNS by stimulating stretch receptors in the lung, which send impulses along afferent fibers of the vagus nerve activating the SNS and increasing the H.R.

Explain why the heart rate and finger pulse change during a Valsalva maneuver. Include in your explanation how changes in arterial blood pressure, peripheral resistance, and autonomic nervous activity bring about these responses.

Raised intrathoracic pressure drives blood from the lungs into the left atrium. This increases stroke volume resulting in a small rise in systolic blood pressure with a consequent small decrease in heart rate. However the increased intrathoracic pressure decreases venous return and stroke volume and therefore systolic blood pressure falls. This fall in BP is detected by the carotid sinus and aortic arch baroceptors, resulting in activation of the baroreflex which acts to maintain constant arterial BP in the short term. To compensate for the fall in BP the baroflex increases sympathetic tone resulting in vasoconstriction and increases heart rate. This stabilizes BP although it remains lower than normal. Release of the pressure initially results in a futher fall in stroke volume as the thoracic vessels fill with blood again. Increased stroke volume and BP return to normal.

Unlike the discrete waveform from an ECG, the EMG waveform is irregular. Why is this?

ECG records electrical activity from the heart. Unlike the heart, skeletal muscle does not contract in a fully synchronized fashion. Instead, EMG records the unsynchronized electrical activity of many muscle fibers.

How did the EMG trace change when you added weight to the volunteer's arm? Based on the data you collected, what can you infer is happening to the muscles as weight is added?

When more books were added, the recorded activity increased. From the recorded data it can be inferred that greater motor unit activity is required to generate more force in order to hold the arm in the same position when more books are added.

Do verbal encouragement and brief rests limit the extent of muscle fatigue?

They have been shown to limit fatigue to some extent during sustained max grip force