Senses, sensory system and flow to higher centres of brain

Question 1

Key Elements of the sensory system + flow from stimulus environment to higher centres of the brain.

Answer 1

Energy contains information about the world.
1. Accessory structure modifies the energy.
2. Receptor transducer energy into a neural response.
3. Sensory nerves transfer coded activity to the central nervous system.
4. Thalamus process and relays neural response.
5. Cerebral cortex receives input and produces the sensation and perception.

Question 2

Transduction:

Answer 2

The process of converting incoming energy into neural activity taking place in neural receptors
When this happens it creates a coded message describing the properties of the stimulus, the brain decodes the neural activity allowing you to make sense of the stimulus to decide (e.g. if you are looking at a cat, dog or human)

Question 3

Encoding:

Answer 3

Process in which information is initially acquired, stored and represented in memory. Involves transforming sensory input into a form that can be stored in the brain. Process of paying attention to a stimulus interpreting it and assigning meaning to it. Different encoding mechanisms may be involved, such as semantic encoding (linking the stimulus to existing knowledge), visual encoding (creating a mental image), or auditory encoding (remembering sounds or spoken words).

Question 4

HEARING -
Physical Stimulus:

Answer 4

1. Difference in air pressure from baseline to peak of the wave is amplitude of sound or intensity.
2. Distance from one wave peak to the next is called wavelength.
3. Frequency (hertz Hz) the number of complete waveforms or cycles that pass by a given point in any one second. One cycle per second = 1Hz

Question 5

HEARING -
Form/function of accessory Structure:

Answer 5

1. Pinna / Auricle (Outer ear) - Visible external part of the ear helps localise the source, amplify certain frequencies, collect sound waves and funnel them into the ear canal.
2. Ear Canal / External Auditory Meatus (Outer ear) - Tube like structure extending from pinna to the tympanic membrane. Helps direct sound waves towards eardrum and protects delicate structures of the middle ear.
3. Tympanic Membrane / eardrum (Middle Ear) - (a tightly stretched membrane in middle ear that generates vibrations that match the sound waves striking it), semitransparent membrane separating the outer ear from the middle ear, vibrating in response to sound waves, transmitting these vibrations into the ossicles.
4. Ossicles / Malleus [hammer], Incus [anvil], stapes [stirrup] (Middle Ear) - Three small bones in middle ear that amplify and transmit vibrations from Tympanic Membrane to inner ear. These bones from chain like structure that amplifies sound waves as they move to the smaller oval window of the inner ear

Question 6

HEARING -
Receptor Cells:

Answer 6

Hair cells located in the cochlea (inner ear) Detect mechanical vibrations produced by sound waves and convert into neural signals sent to the brain for processing. 2 Types - Inner hair cells - Arranged in a single row along length of cochlea responsible for transmitting majority of auditory information to the brain, crucial for detecting sound and transmitting precise information about sound frequency and intensity. Outer Hair Cells - Arranged in three rows along length of cochlea and play a role in amplifying sound signals , can change in length in response to electrical signals. Enhance sensitivity and frequency selectivity of auditory system.

Question 7

HEARING - Psychological correlation of stimulus dimensions:

Answer 7

The physical characteristics determine the psychological dimensions of sound - loudness, pitch and timbre
1. Loudness - Determined by the amplitude of the sound wave - greater amplitude = louder the sound. Loudness is described in (units = Decibels dB) 0dB is the minimum detectable sound for normal hearing.
2. Pitch - Low or High tones depends on frequency of sound waves. High frequency = High pitched. Highest note on piano is about 4000Hz, lowest is about 50Hz. Humans can hear 20Hz - 20 000Hz
3. Timbre - Quality of sound, determined by complex wave patterns. The mixture of frequencies and amplitudes that make up the quality of sound.

Question 8

VISION -
Nature of Physical stimulus:

Answer 8

Light is electromagnetic radiation from 400 nanometers to 750 nanometers - the intensity and wavelength of light waves determines the brightness and colour of visual sensations.
1. Light intensity - physical dimension of lightwave that refers to how much energy the light contains, determines the brightness of light.
2. Light wavelength - Physical dimension of light waves that refers to their length, the distance between peaks in light waves and produces sensations of different colours.

Question 9

VISION - Form/function of accessory structure:

Answer 9

1. Cornea - Curved, transparent, protective layer through which light rays enter the eye.
2. Pupil - An opening in the eye, just behind the cornea, through which light passes.
3. Iris - Colourful part of the eye, constricts or relaxes to adjust the amount of light entering the eye.
4. Lens - The part of the eye behind the pupil that bends light rays, focussing them on the retina.

Question 10

VISION -
Receptors Cells:

Answer 10

Photoreceptors which are specialised cells in the retina converting light energy into nerve cell activity, they contain photopigments which are chemicals the respond to light and assist in converting
1. Rods - Highly sensitive to light photoreceptors that allow vision even in dim light but cannot distinguish colours. More concentrated in outer regions of retina.
2. Cones - Less light-sensitive, responsible for colour vision and visual clarity (visual acuity). Highly concentrated in the centre of the retina in fovea region of retina.

Question 11

VISION - Psychological correlation of stimulus dimensions:

Answer 11

1. Hue - the essential ‘colour’ determined by the dominant wavelength of light.
2. Colour saturation - The purity of colour. A colour more saturated = one wavelength is relatively more intense (contains more energy) than others.
3. Brightness - The overall intensity of all of the wavelengths that make up light.

Question 12

SMELL (Olfactory Perception - the sense of smell) - Nature of Physical stimulus:

Answer 12

Airborne chemicals reach the olfactory area through the nostrils and through the back of the mouth, fibres pass directly from the olfactory area to the olfactory bulb in the brain, from there signals pass to areas such as the hypothalamus and amygdala where they are processed and interpreted as smells.

Question 13

SMELL - Form/function of accessory structure:

Answer 13

Nose, Mouth and upper part of the throat all helping funnels odour molecules to receptors and lungs which help move odour molecules into the mouth and nose.

Question 14

SMELL -
Receptor Cells:

Answer 14

Located within the Olfactory epithelium (tissue lining the upper part of nasal cavity) primary receptors are called olfactory Receptor neurons (ORNs) which have structures called olfactory cilia extend into mucus layer covering Olfactory epithelium. Odourant molecules dissolved in mucus come in contact with olfactory cilia where they bind to proteins known as odourant receptors. When an odourant bind to it’s corresponding receptor it initiates biochemical reactions within the receptor neuron then transmitted to the brain via olfactory nerve where they are process and interpreted as smell sensations. (1000 Different types of receptors)

Question 15

SMELL - Psychological correlation of stimulus dimensions:

Answer 15

1. Intensity - strength or concentration of odourant, high odourant concentrations = more intense evoking strong olfactory sensations and reactions.
2. Quality - Specific character or nature of Courant, different odourants are perceived as having distinct qualities or identities allowing for discrimination and recognition
3. Hedonic Tone - Refers to pleasantness or unpleasantness or natural, plays significant role in determining odour preferences and aversions
4. Familiarity - referring to the degrees to which an odour is recognised with associated past experiences.

Question 16

TASTE -
Nature of Physical stimulus:

Answer 16

Chemical sense particularly for dissolved chemicals that come in contact with taste receptor cells.

Question 17

TASTE - Form/function of accessory structure:

Answer 17

Mouth and Papillae (Bumps on tongue) which serve to move found around your mouth. And taste buds which are small clusters of cells located in papillae and other parts of mouth including the roof and throat. Each taste bud detect different taste chemicals including savoury, sweet, sour, salty and bitter and intimate neural signals sent to the brain for processing.

Question 18

TASTE -
Receptor Cells:

Answer 18

Located within tastebuds known as taste receptor cells or gustatory receptor cells. Have specialised proteins on the surface which bind to to the correspond taste receptor triggering a series of biochemical reactions leading to the generation of electrical signals which are then transmitted to the brain vis the gusty nerve pathways where they are interpreted as taste sensations.

Question 19

TASTE - Psychological correlation of stimulus dimensions:

Answer 19

1. Sweet - taste quality associated with sugars and artificial sweeteners, perceived as pleasurable and associated with energy-rich foods
2. Sour- Associated with acidic substances such as citric acids and citric fruits. Perceived as refreshening or tart
3. Salty - associated with sodium chloride and other salts, perceived as enhancing, sensations of salivation or thirst
4. Bitter - Associated with various compounds including coffee, dark chocolate and some vegetables. Perceived as averse or unpleasant, signal of potentially harmful substance.
5. Umami - Savoury taste of amino acids, particularly glutamate and nucleotides found in food such as meet, cheese and mushrooms, perceived as satisfying and savoury.

Question 20

BODY (Known as Cutaneous Sensors) -
Nature of Physical stimulus:

Answer 20

1. Touch (Tactile sensation) - The physical sensation involving mechanical pressure of deformation applied to the skin. Mechanical forces are exerted onto skins receptors (Mechanoreceptors) generating aural signals transmitted to the brain, different Mechanoreceptors respond to specific aspects of touch (pressure, vibration, stretching and fine touch) Play a role in perceiving textures, shapes, and objects and well as social interactions and communication.
2. Temperature Sensation - Applied temperature to skin. Temperature receptors (Thermoreceptors) detect variations in skin temperature and generate aural signals that are transmitted to the brain. Two types of thermoreceptors 1. Cold receptors - respond to decreases in temoperature 2. Warm receptors- respond to increase of temperature. These receptors help to regulate body temperature and perceive external temperature of objects and environments.
3. Pain sensation (Nociception) - Involves tissue damage or potential tissue damage that activates specialised pain receptors called Nociceptors. Found throughout the body including skin, muscles, joints and internal organs. Respond to harmful stimuli such as pressure, extreme temperatures, chemical irritants, tissue injury. When activated nociceptors generate neural signals transmitted to the brain where they are perceived as pain sensations. Pain serves as a protective mechanism, alerting the body to potential threats or injuries and promoting behaviours to avoid or alleviate harm.

Question 21

BODY - Form/function of accessory structure:

Answer 21

1. Touch - Hair follicles small structures containing hair shafts and associated nerve ending, play a role by detecting movements or displacement of the hairs which can be triggered by light touch or air currents
2. Temperature - Sweat Glands located within the skin and regulate temperature 1. Eccrine sweat glands - smaller sweat glands release sweat onto skin surface 2. Apocrine sweat glands
3. Pain -

Question 22

BODY -
Receptor Cells:

Answer 22

1. Touch - Mechanoreceptors respond to specific aspects of touch (pressure, vibration, stretching and fine touch) Play a role in perceiving textures, shapes, and objects and well as social interactions and communication.
2. Temperature - Two types of thermoreceptors 1. Cold receptors - respond to decreases in temperature 2. Warm receptors- respond to increase of temperature. These receptors help to regulate body temperature and perceive external temperature of objects and environments.
3. Pain - Nociceptors are found throughout the body including skin, muscles, joints and internal organs. Respond to harmful stimuli such as pressure, extreme temperatures, chemical irritants, tissue injury. When activated nociceptors generate neural signals transmitted to the brain where they are perceived as pain sensations.

Question 23

BODY - Psychological correlation of stimulus dimensions:

Answer 23

1. Pain -
   a. Intensity - referring to the severity or strength of the painful stimulus. Higher pain intensity = greater distress and discomfort.
   b. Quality - Refers to specific character or nature, can be described as dull, throbbing, burning or stabbing.
   c. Location - Refers to area where it is experience, influencing the interpretation and what may be the cause.
   d. Duration - Referring to how long the pain lasts, acute, short duration, chronic and persisting, then impacting daily functions and quality of life.
2. Temperature -
   a. Intensity - Refers to the perceived strength or magnitude of the thermal stimulus. Higher temperature = more extreme or uncomfortable
   b. Quality - Refers to specific character or nature, described as hot, warm, cold, or cool. Different temperatures evoke different perceptions of comfort or discomfort.
   c. Location - Refers to the location where thermal stimulus is experiences influencing interpretation and information about surrounding environment or context.
   d. Duration - Referring to how long thermal stimulus persists, occurring briefly, lasting duration can influence their impact on behaviour and comfort levels.
3. Touch -
   a. Intensity - Refers to strength or pressure of tactile stimulus, higher touch intensity may be perceived more forceful or invasive, lower = gentle or comforting
   b. Texture - Perceived smoothness, roughness and other qualities, different textures may evoke different sensory experiences.
   c. Location - Refers to specific area where it is experienced, location influences interpretation and provide information about environment or context.
   d. Duration - How long the stimulus persists, duration can impact sensory processing and perception.

Question 24

VISION -
Trichromatic Theory and Example:

Answer 24

A theory of colour vision identifying three types of visual elements, each of which is most sensitive to different wavelengths of light.
Focusses on mechanisms of colour detection in the retina.
EXAMPLE: You’re looking at a landscape with a blue sky, green tress and red flowers. The blue sky stimulates the blue sensitive cones in your retina, the green trees stimulate the green-sensitive cones in your retina and the red flowers stimulate the red-sensitive cones. From each type off cone responding to their corresponding wavelength of light, the combination all the colours allows your brain to see the full spectrum of colours.

Question 25

VISION -
opponent-process theory and Example:

Answer 25

Opponent theory theory: A theory of colour vision stating that colour-sensitive visual elements are grouped into red-green, blue-yellow, black white elements.
Focuses on how colour information is processes and encoded in the visual system beyond the retina.
EXAMPLE: Using the same example, the blue skies stimulate the blue-senfstice cones in your retina, as you continue to look at the blue sky the cones become fatigued, you shift your vision to a white surface or you close your eyes and you briefly see a yellow hue, yellow is the opponent colour of blue. You look at the Red flowers, the red-sensitive cones become fatigued and you close your eyes and you see a green hue.

Question 26

HEARING - Determining frequency/location of sound
Place Theory (Frequency Detection):

Answer 26

A theory that hair cells at a particular place on the basilar membrane respond most to a particular frequency of sound - Low vibration cause maximal vibration near apex - high frequency cause maximum vibration near the base of the cochlea. The brain interrupts the location of the maximum vibration as an indication of the frequency.

Question 27

HEARING -
Volley Theory (Frequency matching theory):

Answer 27

A theory of hearing sating that the firing rate of an acoustic nerve matches a sound waves frequency. Proposing that groups of auditory neurons can work together to encode the frequency of sound waves, particularly for frequencies higher than what can be detected by individual neurons firing at their maximum rates.

Question 28

HEARING -
Spectral Cues (Sound Localisation):

Answer 28

The shape of the Pinna (Outer Ear) and the head cause subtle modifications to the frequency of incoming sounds, creating spectral cues that our brain uses to localise sounds in space, particularly high frequencies, the brain uses spectral cues from both ears to determine the direction of sound source.

Question 29

HEARING - Intramural Level Difference (ITD) (Sound Localisation)

Answer 29

The brain compares intensity (loudness) of sound arriving at each ear, the head creates a barrier causing sounds to be louder in the ear closest to sound source and quieter in the ear furthest away. The brain uses this difference in intensity to determine the direction of sound source.

Question 30

PAIN -
Gate Theory:

Answer 30

A theory suggesting that a functional ‘gate’ in the spinal cord can either let pain impulses travel upwards to the brain or block their progress. (Melzack and Wall, 1965)
Gate control Theory suggests that attention, expectation and emotional state can control the transmission of pain signals through the spinal cord ‘gate.’ Positive expectations and distractions can ‘close the gate’ reducing the transmission of pain signals. While negative expectations can ‘open the gate.’

Question 31

PAIN -
Culture:

Answer 31

Cultural beliefs and attitudes can influence how individuals perceive and experience pain. Cultural norms regarding expression, coping and beliefs about the cause of pain can shape individuals experience with pain.
Can also influence healthcare-seeking behaviours and treatment preferences for pain management

Question 32

PAIN -
Expectation:

Answer 32

Expectation and beliefs about pain can influence the perception and experience of pain, if expected to be highly painful than they may experience intense pain.

Question 33

PAIN -
Analgesics:

Answer 33

(Analgesia - the absence of pain sensations in the presence of a normally painful stimulus.) Gate Control theory suggest that analgesic medications can modulate pain transmission by affecting the activity of neurons in the spinal cord ‘gate’ E.G. opioids can inhibit transmission of pain signals by binding opioid receptors on neurons in the spinal cord, reducing pain perception. Can be influenced by pain sensitivities, tolerances and response to treatment.