3A4 Sensory Information Processing in Animals

Question 1

Define:

stimulus

In sensory processing

Answer 1

A detectable change in the internal or external environment.

Stimuli can include light, sound, chemicals, temperature, or mechanical forces, triggering responses in sensory receptors.

Question 2

What is the role of sensory receptors?

Answer 2

To detect stimuli and convert them into neural signals.

Sensory receptors act as biological transducers, converting external stimuli into electrical impulses that travel to the nervous system for processing.

Question 3

Why do animals need sensory systems?

Answer 3

To detect and respond to environmental changes for survival.

Sensory systems enable animals to locate food, avoid predators, recognize mates, and navigate complex environments, improving survival and reproduction.

Question 4

What are the five main types of stimuli animals detect?

Answer 4

1. Light
2. Sound
3. Chemical
4. Mechanical
5. Thermal

Light - e.g., visible, ultraviolet

Sound - e.g., vibrations, echolocation

Chemical - e.g., smell, taste

Mechanical - e.g., touch, pressure, motion

Thermal - e.g., heat, cold

Question 5

What type of stimulus do photoreceptors detect?

Answer 5

Light

Photoreceptors in the eyes (rods and cones) respond to changes in brightness and color, playing a key role in vision.

Question 6

True or False:

Chemical stimuli are only detected through taste.

Answer 6

False

Chemical stimuli are detected through both taste (gustation) and smell (olfaction), often working together to enhance perception of food and environmental cues.

Question 7

Define:

mechanoreceptors

Answer 7

Receptors that detect touch, pressure, and vibration.

Mechanoreceptors are found in skin, muscles, and the inner ear, playing roles in touch perception, proprioception, and hearing.

Question 8

What receptors detect temperature changes?

Answer 8

Thermoreceptors

Thermoreceptors help regulate body temperature by detecting heat or cold and sending signals to the brain to trigger responses such as sweating or shivering.

Question 9

What is the function of chemoreceptors?

Answer 9

They detect chemical signals in the environment.

Chemoreceptors play vital roles in smell, taste, and internal regulation, such as detecting oxygen levels in blood.

Question 10

True or False:

All sensory receptors are located in the brain.

Answer 10

False

Sensory receptors are distributed throughout the body, in organs such as the skin, ears, tongue, and eyes, and send signals to the brain for processing.

Question 11

What organ detects light in vertebrates?

Answer 11

The eye

The eye contains specialized photoreceptors—rods (for low light) and cones (for color vision)—that send signals to the brain via the optic nerve.

Question 12

Why do nocturnal animals have larger eyes?

Answer 12

To improve light collection for better night vision.

Larger eyes contain more rods, which are highly sensitive to dim light, allowing nocturnal animals to see in low-light conditions.

Question 13

How do animals detect sound?

Answer 13

Through mechanoreceptors in the ear that sense vibrations.

The ear’s structures convert sound waves into neural signals, with the cochlea playing a crucial role in detecting different sound frequencies.

Question 14

What is the process of converting stimuli into electrical signals?

Answer 14

Sensory transduction

Sensory transduction occurs at the receptor level, where stimuli are converted into nerve impulses that the brain interprets.

Question 15

What brain region processes vision?

Answer 15

The occipital lobe

Located at the back of the brain, the occipital lobe interprets visual information received from the retina.

Question 16

Why do dogs have a stronger sense of smell than humans?

Answer 16

They have more olfactory receptors and a larger olfactory bulb.

A dog’s sense of smell is estimated to be 10,000 to 100,000 times more sensitive than a human’s due to their extensive olfactory receptor network.

Question 17

Fill in the blank:

The _______ lobe processes auditory information.

Answer 17

temporal

The temporal lobe interprets sound signals from the cochlea, allowing the perception of pitch, volume, and direction.

Question 18

How do bats use echolocation?

Answer 18

They emit sound waves and interpret returning echoes.

Echolocation allows bats to detect objects in complete darkness by analyzing sound reflections.

Question 19

What is the main pathway for sensory signals to reach the brain?

Answer 19

Sensory neurons

Sensory neurons transmit signals from receptors to the spinal cord and brain for processing.

Question 20

Define:

nerve impulse

Answer 20

An electrical signal that travels along a neuron.

Nerve impulses, or action potentials, are generated when a stimulus exceeds the receptor’s threshold, causing ion movement across the cell membrane.

Question 21

What structure transmits nerve impulses between neurons?

Answer 21

Synapse

A synapse is the gap between neurons where neurotransmitters carry signals from one cell to another.

Question 22

Why are myelinated neurons faster in signal transmission?

Answer 22

The myelin sheath insulates axons and speeds up impulse conduction.

In saltatory conduction, impulses jump between gaps in the myelin (nodes of Ranvier), increasing transmission speed.

Question 23

True or False:

Nerve impulses travel in both directions along a neuron.

Answer 23

False

Nerve impulses travel in one direction, from the dendrites through the axon to the synapse.

Question 24

Fill in the blank:

The ______ sheath increases the speed of nerve impulse transmission.

Answer 24

myelin

The myelin sheath is made of fatty tissue that protects axons and enhances signal conduction.

Question 25

What part of the brain **processes** sensory information?

Answer 25

The cerebral cortex ## Footnote The *cerebral cortex* receives and interprets sensory signals, with specialized areas for vision, hearing, touch, and taste.

Question 26

# Define: thalamus | *in sensory processing*

Answer 26

A brain structure that **relays sensory signals** to the cerebral cortex. ## Footnote The **thalamus** acts as a *sensory gateway*, filtering and directing sensory information to the appropriate brain regions.

Question 27

Why does the brain **filter** sensory input?

Answer 27

To **focus** on relevant stimuli and **avoid** sensory overload. ## Footnote The *reticular activating system* helps prioritize important stimuli while ignoring background noise.

Question 28

# Fill in the blank: The \_\_\_\_\_\_ lobe **processes** touch and body sensations.

Answer 28

parietal ## Footnote The *parietal lobe* interprets sensory input from the skin, muscles, and joints, allowing for spatial awareness.

Question 29

# True or False: The brain processes all sensory input **equally**.

Answer 29

False ## Footnote The brain **prioritizes** stimuli based on importance, attention, and survival relevance.

Question 30

# Define: motor response

Answer 30

A **physical reaction** triggered by sensory input. ## Footnote *Motor responses* can be voluntary (e.g., moving your hand) or involuntary (e.g., reflexes).

Question 31

What part of the nervous system **controls** reflex actions?

Answer 31

The spinal cord ## Footnote **Reflexes** are processed by the *spinal cord*, bypassing the brain for faster responses.

Question 32

Why are reflexes **faster** than voluntary responses?

Answer 32

Reflexes **bypass the brain** and are processed by the spinal cord. ## Footnote Reflex arcs involve sensory neurons, interneurons, and motor neurons, ensuring **rapid** reactions.

Question 33

What are the **three main types** of responses to sensory stimuli?

Answer 33

1. Reflexive responses 2. Behavioral responses 3. Cognitive responses ## Footnote **Reflexive responses** - automatic (e.g., blinking) **Behavioral responses** - voluntary (e.g., moving away from heat) **Cognitive responses** - involving memory and learning

Question 34

# Define: sensory memory

Answer 34

**Short-term storage** of sensory information. ## Footnote *Sensory memory* holds information for milliseconds to seconds, allowing the brain to process stimuli before deciding whether to store it.

Question 35

What **brain structure** is essential for memory formation?

Answer 35

The hippocampus ## Footnote The **hippocampus**, located in the temporal lobe, consolidates short-term memories into long-term storage.