Biology 176

Name Leanne Cubar

Lab Partner Brenda AguirreLab Report: Sensory Physiology (Special Senses)Activity 4: Predicting the Effects of Visual Pathway Lesions:Study the diagram of the visual pathway to predict the effect of lesions on vision.

1. Right optic nerve:

2. Through the optic chiasm:

3. Left optic tract

4. Right occipital cortex Activity 5: The Blind Spot:Record your observations:

Have your lab partner record the distance (metric units) at which the dot disappears:

Right eye 6.5 cmLeft eye 6.7 cm

Question:

5. What is the anatomical basis for the blind spot? The blind spot is the optic disk. The reason it is a blind spot is because the that is focused on this region cannot be seen.Activity 6: Accommodation for near vision:Record your observations:

Near Point for right eye: 9.1 cmNear Point for left eye: 8.1 cm

Questions: 1. Explain how the eye focuses on near objects:

a) When focusing on near objects, the smooth muscle on the ciliary body to the lens contracts and the lens becomes more spherical. b) What is happening to your lab partners pupils when they change their focus from a distant object to a close object?

My partner's pupil got smaller as she focused on the object. c) What is happening to the shape of the lens of the eye as it focuses for near vision (you cant observe this directly)?

The shape of the lens becomes more spherical. d) How do the eyes move (adduct/abduct, toward nose/away from nose) when focusing on a near object compared with looking at an object in the distance?

The eyes moved away from the nose when focusing on a near object compared to looking at an object in the distance. 2. How does the near point change as people become older? Explain why.

a) The near point changes due to presbyopia. It is when the lens becomes less elastic and focusing on close objects become more difficult. This happens as people get older.

Activity 10: Testing for Binocular Vision:Questions:

1. What is meant by binocular vision?

This is when the left and right fields of vision overlap and combine the view seen from the left and right eye.

2. What advantage(s) does binocular vision impart to the organism? Supplemental Activity: The positive after-image:Record your observations:

When the test was done, my partner began to see a dotted after-image. Questions:

1. What is the biological explanation for the negative after-image?

2. What is the explanation for the after image of the colored object or pattern?

Hearing and Equilibrium Activity 4:

1. Explain how you would test the hearing of a patient to determine if they have a conduction block or sensorineural deafness.

Barany Test (Induction of Nystagmus and Vertigo):Record your observations (sensitivity of movement and direction detection).

Record your observations (Rotational induction of the VOR and nystagmus). Which way did you spin your lab partner and which way did the eyes move?

Question:

1. What do you think the purpose of the eye movements are?

2. What structures in the brain (including cranial nerves) do you think are involved with this reflex? Exercise 26: Taste and smell:Question:

1. Why do you think the sense of smell is necessary for taste discrimination?

2. How are the senses of taste and smell similar?

3. How do they differ?

4. Why is saliva important for taste?

5. Why is mucous important for smell?

Distribution of taste budsPlot the distribution of each taste sensation on an outline of a tongueBitter:

Sweet:

Sour:

Salt:

6. Do you agree or disagree with the classic Tongue Map model. Explain your reasoning based on your observations.