Quiz 3 Study Guide (1).pdf

Eye Ocular Diseases Presbyopia (lens): Loss of lens elasticity with age, causing difficulty focusing on near objects. Cataracts (lens): Hardened, opaque lens leading to impaired light transmission, common in the elderly. Glaucoma (optic nerve): Compression or degeneration of the optic nerve, pot...

Eye Ocular Diseases Presbyopia (lens): Loss of lens elasticity with age, causing difficulty focusing on near objects. Cataracts (lens): Hardened, opaque lens leading to impaired light transmission, common in the elderly. Glaucoma (optic nerve): Compression or degeneration of the optic nerve, potentially associated with high intraocular pressure. Color Blindness (cones of retina): Impaired color vision due to defective cones, with red-green colorblindness being the most common, often an X-linked recessive disorder. Afferent Pupillary Defect (APD) (retina/optic nerve) - When light is shone into the affected eye, instead of constricting, the pupils may dilate slightly or fail to constrict as much. Disease Eye Structure Affected Description Presbyopia Lens Loss of elasticity of lens with age, thus increasing difficulty when focusing up close; One of the reasons NPA worsens w/ age; Often colloquially called “old eye” Cataracts Lens Hardened, opaque lens, resulting in impaired light transmission, especially in elderly; Because lens separates anterior segment from posterior segment, light cannot enter the posterior segment is easily, so then it cannot reach the retina, where the photoreceptors are located Afferent Pupillary Iris Muscles, which control Pupil Basically, it means that instead of a pupil Defect (APD) Size constricting like it should when light shined into it, it dilates (which is abnormal) Color Blindness Cones of Retina Impaired color vision due to specific cones; X-linked recessive red-green color blindness most common (You do not have to know that chart on slide Lab 8, 52 that you can barely see) SPP Color Plates Test or Ishihara Color Test used to detect and diagnose type of color blindness Glaucoma Optic Nerve Compression or degeneration of Optic Nerve, which results in impaired transmission of visual impulses (action potentials) all way to brain Tests of Visual Functions Visual Cortex: Located in the occipital lobe of the brain. Tests of Visual Function 1. Blindspot Test: Optic Disc ○ Determines the position of the optic disc using a card with a dot and X. ○ Moving the card closer causes the X or dot to disappear when testing each eye. ○ An equation calculates the distance between the fovea centralis and optic disc. 2. Ishihara Color Vision Test/SPP Color Vision Test: Cones ○ Tests for color vision. ○ Identifies color blindness caused by anomalies in specific cones. ○ Identify number from SPP color plates 3. Near Point of Accommodation (NPA): Ciliary body/muscle lens ○ Tests closeness of vision. ○ Accommodation: Ciliary body changes lens shape for near focus (rounder for close, flatter for distant vision). ○ NPA worsens with age due to presbyopia (loss of lens elasticity). ○ Near Triad: Pupils constrict, eyes converge, and lens accommodates when focusing on close objects. ○ Method: Slowly bring an object closer to the eyes until it blurs.  4. Photopupillary Reflex: Iris Sphincter Muscles ○ Autonomic Reflex: Controlled by the parasympathetic branch. ○ Normal Response: Pupils are equal, round, and reactive to light (PERRL/-APD). ○ Pupils should not dilate in response to light; dilation indicates a potential Afferent Pupillary Defect (APD). ○ Result: Pupils constrict in both eyes (consensual response) because the motor pathway to both eyes' iris sphincter muscle is the same. 5. Positive Afterimage: Retina rods and cones ○ Stimulus: white bulb ○ Definition: light perception/glow/fuzzy white after viewing a bright light. ○ Caused by fatigue of photoreceptors. 6. Negative Afterimage: Retina: Cones ○ Definition: A dark spot or complementary color seen after prolonged exposure to a light or stimulus. ○ Red - green ○ Blue - yellow ○ Black - white ○ Caused by overstimulation of cones, making them less responsive. Reflex Arc Components (in order): Receptor/Sensor: Detects the stimulus. Afferent (Sensory) Neuron: Sends the signal to the CNS. Integration Center/Integrator: ○ CNS synapse(s) in the brain or spinal cord. ○ May involve interneurons. Efferent (Motor) Neuron: Sends the signal to the effector. Effector: Muscles or glands respond to the stimulus. Types of Reflex Responses: Ipsilateral Response: Reflex occurs on the same side of the body as the stimulus. Contralateral Response: Reflex occurs on the opposite side of the body as the stimulus. Consensual Response: Reflex occurs on both sides of the body, even if the stimulus is applied to only one side Somatic Reflexes: Patellar Reflex Stimulus: Rubber mallet. Receptor: Muscle spindles Sensory Fibers: afferent neurons - enter posterior horns spinal cord Integrator: Spinal cord Motor Fibers: Efferent fibers Come out of anterior horns spinal cord Release ACh onto quadriceps femoris muscles Effectors: Quadriceps femoris muscles contract, causing knee extension. Process: Somatic Reflex: Involves somatic motor neurons that control skeletal muscles. Mechanism: Striking the patellar tendon stretches the muscle spindles. Sensory/afferent neurons send signals to the spinal cord posterior horns. These neurons synapse directly with motor/efferent neurons in the spinal cord anterior horns. Motor fibers release Acetylcholine (ACh) onto the quadriceps femoris muscles, causing contraction. Normal Ipsilateral Response: ○ The quadriceps femoris muscle contracts. ○ The knee extends. ○ Hamstrings relax/stretch. Characteristics: ○ It is a monosynaptic reflex ( 1 synapse, no interneurons ) ○ It is ipsilateral. Autonomic Reflexes: Photopupillary Reflex Stimulus: Light shone into one eye. Normal Responses: ○ Direct Response: The pupil in the same eye constricts (miosis). ○ Consensual Response: The pupil in the opposite eye also constricts (miosis). Driven by: The parasympathetic nervous system. Abnormalities: ○ Positive Afferent Pupillary Defect (APD): Pupil dilates instead of constricting in response to light. ○ Unequal pupil sizes or sluggish reactivity.  ANS: Sympathetic vs Parasympathetic Photoreceptors Rods Cones Photopigments Rhodopsin Red, Blue, and Green Photopsins Sensitivity Lower Higher Perception Dim light Bright light No color vision Color Vision Motion Central Vision (Not fine detail) Fine Detail Poor contrast sensitivity & resolution High contrast sensitivity & resolution (Lower Visual Acuity) High Visual Acuity Distribution Peripheral Retina, so more Central Retina. Highest in MACULA; responsible for peripheral vision FOVEA has CONES ONLY EAR 1. Outer Ear: ○ Auricle/Pinna: Directs sound waves into the ear canal. ○ Ear Canal: Transmits sound to the tympanic membrane. ○ Tympanic Membrane (Eardrum): Vibrates in response to sound. 2. Middle Ear: ○ Ossicles: Malleus: Attached to the eardrum (tympanic membrane), transmits vibrations to the incus. Incus: Transmits vibrations from the malleus to the stapes. Stapes: Transfers vibrations to the oval window of the cochlea. ○ Eustachian Tube: Equalizes pressure between the middle ear and the environment. 3. Inner Ear: ○ Cochlea: Converts mechanical vibrations into electrical signals via the organ of Corti.  ○ Vestibule: Maintains static equilibrium. ○ Semicircular Canals: Detect dynamic equilibrium. 4. Auditory Nerve Pathway: ○ Cochlear Nerve: Transmits auditory signals to the brain. ○ Auditory Cortex: Located in the temporal lobe; processes and interprets sound. Sound Interpretation in the Auditory Cortex: sound is interpreted in the auditory cortex of the temporal lobe of the brain. Rinne Test: Hearing Procedure: ○ Strike a tuning fork and place it on the mastoid process (behind the ear). ○ When the sound is no longer heard, move the fork to just outside the ear canal. (perpendicular) to test air conduction (AC) ○ Ask the individual to indicate when the sound stops. Interpretation: AC > BC: Normal hearing. BC > AC: Conductive hearing loss. ○ Cotton affects AC of the ipsilateral ear the most.  HEART Order of Blood Flow 1. Systemic Veins: start of O2 poor 2. Venae Cavae: ○ Superior Vena Cava. ○ Inferior Vena Cava. 3. Right Atrium: O2-poor blood enters the heart. ○ Blood flows through the Tricuspid Valve. 4. Right Ventricle: Pumps O2-poor blood. ○ Blood flows through the Pulmonic (Semilunar) Valve. 5. Pulmonary Trunk: Blood exits the heart. 6. Pulmonary Arteries: Blood flows to the lungs. ○ Includes Pulmonary Arterioles and Pulmonary Capillaries. 7. Pulmonary Veins: start of O2 rich 8. Left Atrium: Receives O2-rich blood. ○ Blood flows through the Mitral Valve. 9. Left Ventricle: Pumps O2-rich blood. ○ Blood flows through the Aortic (Semilunar) Valve. 10. Aorta / Aortic Arch: Blood exits the heart. 11. Systemic Arteries: Distributes O2-rich blood to the body. Includes Systemic Arterioles and Systemic Capillaries. 12. Systemic Tissues: O2 is delivered, and blood becomes O2-poor. CHAPTER 9 EMBRYOLOGY CHICK EMBRYO DEVELOPMENT  Chick tissue Organizer: Hensen’s Node (Primitive Node) Frog tissue Organizer: Dorsal Blastopore Lip CHAPTER 10  Agglutination: Clumping of RBCs when antibodies in the plasma react with foreign antigens on RBCs. Bone/Type Long Bones: Femur Short Bones: Carpals Flat Bones: Sternum Irregular Bones: Vertebrae Sesamoid Bones: Patella Blood pressure: Systolic - top number/heart contracts Diastolic - bottom number/heart relaxes