Exercise 23 24 General Sensation Vision Sensory Receptors
- Slides: 28
Exercise 23 & 24 General Sensation & Vision
Sensory Receptors • Structures specialized to respond to stimuli • Activation of sensory receptors results in depolarizations that trigger impulses to the CNS • The realization of these stimuli, sensation and perception, occur in the brain
• Mechanoreceptors – respond to touch, pressure, vibration, stretch, and itch • Thermoreceptors – sensitive to changes in temperature • Photoreceptors – respond to light energy (e. g. , retina) • Chemoreceptors – respond to chemicals (e. g. , smell, taste, changes in blood chemistry) • Nociceptors – sensitive to pain-causing stimuli Receptor Classification by Stimulus Type
Receptor Class by Location: Exteroceptors • Respond to stimuli arising outside the body • Found near the body surface • Sensitive to touch, pressure, pain, and temperature • Include the special sense organs
Simple Receptors: Unencapsulated Table 13. 1. 1
Simple Receptors: Encapsulated Table 13. 1. 2
Simple Receptors: Encapsulated Table 13. 1. 3
Adaptation of Sensory Receptors • Adaptation occurs when sensory receptors are subjected to an unchanging stimulus – Receptor membranes become less responsive – Receptor potentials decline in frequency or stop
Chemical Senses • Chemical senses – gustation (taste) and olfaction (smell) • Their chemoreceptors respond to chemicals in aqueous solution – Taste – to substances dissolved in saliva – Smell – to substances dissolved in fluids of the nasal membranes
Eye and Associated Structures • 70% of all sensory receptors are in the eye • Most of the eye is protected by a cushion of fat and the bony orbit • Accessory structures include eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
Palpebrae (Eyelids) Figure 15. 5 b
Extrinsic Eye Muscles Figure 15. 7 a, b
Structure of the Eyeball Figure 15. 8 a
Pupil Dilation and Constriction Figure 15. 9
Sensory Tunic: Retina Figure 15. 10 a
Anterior Segment Figure 15. 12
Focusing for Distant Vision • Light from a distance needs little adjustment for proper focusing • Far point of vision – the distance beyond which the lens does not need to change shape to focus (20 ft. ) Figure 15. 17 a
Focusing for Close Vision Figure 15. 7 b
Problems of Refraction Figure 15. 18
Astigmatism
Visual Pathways Figure 15. 23
Terms • • Accommodation Emmetropia: normal vision Myopia: near-sigthedness Hyperopia: far-sightedness Presbyopia: “old vision” Glaucoma: intraocular pressure imbalance Cataract: clouding of the lens Conjunctivitis: inflammation of the conjunctiva
The Retina
Retina
- Classification of sensory system
- Types of thermoreceptors
- Classification of sensory receptors
- Exteroceptors
- Classification of sensory receptors
- Classification of sensory receptors
- Dermatome
- Sensory receptors
- Proprioceptors
- U
- Tectorial membrane
- Human vision vs computer vision
- General studies primary 1 exercise
- Sensation seeking
- Sciatic sensory distribution
- Chapter 5 sensation and perception
- Sensation seeking significato
- What are the gestalt principles of visual perception?
- Chapter 3 sensation and perception
- 6 principles of sensation
- Perceptual set ap psych
- Thermoreceptors
- Types of sensation
- Difference between sensation and perception
- Sensation and perception crossword review answers
- Chapter 3 sensation and perception
- Types of sensation
- Sensation vs perception
- Back pain classification