Psych Exam 3

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Sensory Receptors
Pacinian Corpucles
Free Nerve Endings
Merkel’s discs
Meissners corpuscles
Ruffini Corpuscle

Pacinian Corpuscle- graded potential receptor, sensitve to vibration and pressure
Mechano Receptors
Free Nerve endings- unspecialized, sensitive to heat, pain and itch and cold
Merkel’s discs- most precise receptor, sensitve to edge, and light touch
meissner corpuscle- sensitive to light touch and changes in stimuli
Ruffini Corpuscle- detects skin stretching and info about movement

SomatoSensory Pathway

Nerves enter the spinal cord through Dorsal Root, Then projections are sent to dorsal column, then are projected to the thalamus. Finally ends up at in the primary sensory cortex

Dorsal Column-responsible for fine touch & proprioception

Receptive Fields
Sensory Adaptation
Tonic Vs Phasi Activation
Labeled Lines
Sensory Mapping/Sensory Homunculus

Receptive Fields-Areas detected by individual receptors
Sensory Adaptation-Decreased response overtime
-tonic-longer lasting, more sustained release
-Phasi-has peaks, shorter, longer, more bursts
Labled lines-Distinct pathways for sensory information
Sensory Mapping/Sensory homunculus-represents body regions in the cortex. 

-the brain/somatosensory cortex receives information from specific body parts. They are mapped within the homunculus. The most sensitive body parts are the lips and fingers.

Pain:What kind of receptor is impacted?
what is TRPV1?
Afferent fibers (Aδ and C fibers):
Periaqueductal gray
Spinothalamic projections
Placebo effect, endorphin and cingulate cortex

Pain impacts free nerve ending receptors. Are sensed immediately.
TRPV1- Type of pain receptor sensitive to heat and pain. Can be activated through temperatures as well as Capsaicin
Afferent Fibers
A delta- Lightly myelinated, larger diameters, fast conducting fibers that carry sharp, localized pain signals
C-fibers- Unmyelinated, smaller diameter fibers that carry dull, burning pain
PAG Gray matter-pain inhibition, responsible for sending IPSPS or EPSP signals to the dorsal region which ultimately close or open the gate for pain signals
Spinothamlamic Projections- pain pathway through the spinal cord and towards the brain for processing
cingulate cortex- responsible for uncomfortable feeling when dealing with pain stimulants

Vision?
Iris?
Retina?
Lens?
Ciliary Muscle?
Optic Nerve
Optic Disk?
Fovea?

Vision-visual system that converts light into neural signals and processes them to form visual perception.
Iris: Controls the amount of light that enters the pupil
Retina: Contains photoreceptors (rods/cones") that convert light into neural signals
Lens: structure that focuses light into back of retina-used for sharp vision
Ciliary Muscle-controls the shape of lens
Optic Nerve: Bundle of axons that leave the eye towards the brain
Optic Disk- Portion of the retina that does not contain any photoreceptors, blind spot where the optic nerve exits the retina
Fovea- region of the retina with high visual visual activity due to high concentration of cones AKA sharp vision

Define Rods and Cones

Rods: Specialized for scotopic vision AKA low light condition, sensitive to low light
Cones: Photopic vision, aka color and bright light, responsible for visual activity and color/chromatic vision

What is the general pathway for vision WITHIN the retina? What are horizontal cells? What are Amacrine cells?

Bipolar cells get their input from photoreceptors, and synapse on ganglion cells, which their axons make up the optic nerve. Finally gets carried out to the brain

Photoreceptors and Photopigments  (Rhodopsin, Retinal): Roles of opsin.
What is Lamella?
What are photopigments?
what is Opsin?
what is Retinal?
what is Rhodopsin?

Photoreceptors change in membrane potential depending on lighting. releases nuerotransmitters in dark.

VIsual Pathway overall
What is LGN?

Retina-optic nerve-optic chiasm-optic tract-LGN (Thalamus)-optic radiations-Primary visual cortex
LGN- lateral Geniculate Nucleus-relay system for visual processing
Ganglion Cell axons make action potentials, are sent to the brain. Their axons make up the optic nerve, reaching the occipital cortex. In most animals and people, some or all optic nerves cross the midline at the optic chiasm, after crossing, known as the optic tract.
Crossing at optic chiasm

• Left visual field → right brain

• Right visual field → left brain

Thalamus: organizes info to parvocellular and magnocellular.
What is parvocellular and what is magnocellular?

Parvocellular- small receptive fields in the retina, mostly near the fovea, responsible for visual detail, and colors due to cones
Magnocellular- larger receptive fields in the retina,not senstive to color and instead, responds stongly to moving stimuli and to large overall patterns due to rods

Ventral and Dorsal Streams

Ventral- The “What” Stream, goes through temporal cortex, specializes in identifying and recognizing objects
Dorsal- The “Where” Stream, goes through parietal cortex, important for visually-guided movements

Visual Stream Deficits
Ventral deficits:
Visual Agnosia
Prosopagnosia

Dorsal Deficits:
Balint’s Syndrome
Optic Ataxia
Ocular Ataxia
Visual Neglect
Akinetopsia

Visual Agnosia-Inability to perceive objects
prosopagnosia- Inability to recognize faces
Dorsal Deficits:
Balints Syndrome-damage to occipital and parietal regions of brain leads to side effects
SE1: Object Ataxia- difficultly in reaching for objects, you and see and recognize the object but have trouble reaching it
SE2: Ocular Apraxia-difficuly in visual scanning, can’t focus on a single object, mid goes to another object
Visual Neglect- neglecting events in the visual field
Akinetopsia- inability to percieve movement

Types of Chemical Communitcation
Synape
Endorcrine
Pheromone
Allomone

Synapse: Neurotransmitter release and diffusion across a synapse
Endorcrine: Hormone is released into bloodstream and acts on selective target issues
Pheromone: Chemicals released outside the body to affect other individuals of the SAME species
Allomone: Chemicals released outside the body to affect other individuals of DIFFERENT species

Define Hormone, Endocrine glands and Exocrine Glands

Hormones are chemicals secreted by a cell group.
Endocrine Glands-release hormones within the body
exocrine glands-release hormones outside the body

Different kinds of structures of Hormones
Protein Hormone
Amine Hormone
Steroid Hormone

List their effects

Protein hormone-composed of a string of amino acids
Amine Hormones-Composed of a modified single amino acid
Steroid Hormone-Composed of cholesterol and made of four rings of carbon atoms

Protein and Amine Hormones bind to a specific receptor on the surface of a cell and then cause the release of a second messenger
Steroid Hormones pass through the cell membrane and bind to receptors IN the cell

Protein and Amine acids act faster, but steroid hormones have a longer lasting impact

Hypothalamic-pituitary axis

The Hypothalamus acts as the command center, Also tells the pituatary gland to release hormones. Hypothalamus releases releasinhg hormones to tell Anterior Pituitary gland to release tropic hormones.

Posterior Pituitary Gland And Anterior Pituitary Gland

The Posterior pituitary gland already recieves synthesized hormones. However, they release Oxytocin and Vasopressin. Oxytocin is responsible for parenting and reproductive behavior. Vasopressin is responsible for increasing blood pressure and water conservation

The Anterior Pituitary gland releases tropic hormones that act on specific target glands. They release mutliple things
Hypothalamus releases GnRH, releases Anterior’s FSH-Sex hormone
Hypothalamus releases TRH,releases Anterior’s TSH-Thyroid hormone production
Hypothalamus releases PRH, releases Anterior’s PRL-Milk Production
Hypothalamus releases GHRH, releases Anterior’s GH- IGF production (Growth)
Hypothalamus releases CRH, releases Anterior’s ACTH-Cortisol production

Estrogen, Progesterone, Testosterone, Ovalutory cycle

The ovulatory cycle begins when

– FSH stimulates ovarian follicles to grow

and secrete estrogens

– LH then stimulates ovulation and formation

of a corpus luteum, which secrete

progesterone

Estrogen also plays a role in regulating memory

Define Homeostasis, set point, set zone, and negative feedback

Homestasis-Maintainance of balance within the body
Set point-single value that the body works to maintain
Set Zone- range in which the body may be satisifed
Negative Feedback-Process in which the body attempts to balance the body when the set point is met