biology brain nd eyes

What are the two types of cells in the nervous system?

Neurons and glia.

What are the four specialized functions of neurons?

1. Receive information, 2. Process information, 3. Conduct electrical signals, 4. Communicate with other cells.

What is the role of dendrites in a neuron?

Dendrites receive information from other neurons.

What happens in the cell body of a neuron?

It integrates incoming information and produces an action potential if the signal is strong enough.

What is an axon?

The part of a neuron that conducts electrical signals to the synaptic terminal.

What is the function of the synaptic terminal?

It communicates with other cells by releasing neurotransmitters.

What are Nodes of Ranvier?

Gaps in the myelin sheath where the electrical impulse signal is regenerated.

What is myelin?

An insulating layer around neurons that increases the speed of electrical conduction.

What is the resting potential of a neuron?

Typically around -60 mV, indicating a negatively charged interior.

What triggers the generation of an action potential?

When the membrane potential reaches the threshold potential.

What is an All or None Response in neurons?

A response where the neuron either fires an action potential or does not, regardless of the strength of the stimulus.

What occurs during depolarization of a neuron?

Sodium channels open, allowing Na+ ions to rush into the cell, making the inside positive.

What happens after depolarization?

Sodium channels close and potassium channels open, allowing K+ to exit the cell, restoring polarity.

What is the refractory period?

The time after an action potential during which a neuron cannot be restimulated.

What is the function of the Sodium-Potassium Pump?

It restores the original ionic conditions by pumping Na+ out and K+ into the cell.

How do neurons communicate at synapses?

By releasing neurotransmitters from the presynaptic neuron into the synaptic cleft.

What are excitatory postsynaptic potentials (EPSP)?

Potentials that bring the resting potential closer to the threshold, making action potential generation more likely.

What are inhibitory postsynaptic potentials (IPSP)?

Potentials that move the resting potential further from the threshold, making action potential generation less likely.

What is reuptake in neurotransmitter recycling?

The process by which the presynaptic neuron reabsorbs neurotransmitters from the synaptic cleft.

What is the role of acetylcholinesterase?

An enzyme that breaks down leftover acetylcholine in the synaptic cleft.

What is the role of wiring patterns in the brain?

They help distinguish the type of stimulus, such as light or sound.

What can abnormal stimuli cause?

Abnormal responses, such as seeing stars after being hit on the head.

What are the three important neurotransmitters mentioned?

Acetylcholine, dopamine, and epinephrine.

What do action potentials in the optic nerves represent?

Light.

What do action potentials in the auditory nerves represent?

Sound.

What is synesthesia?

A condition where stimulation of one sensory pathway leads to automatic, involuntary experiences in a second sensory pathway.

How is the intensity of a stimulus coded in the nervous system?

By the frequency of action potentials and the number of neurons that fire.

What is convergence in the context of the nervous system?

When many neurons funnel their signals to fewer decision-making neurons.

What is divergence in neural signaling?

When a few decision-making neurons send action potentials to many other neurons to elicit complex responses.

What is the role of sensory neurons?

To receive information from the environment and convey it to the central nervous system (CNS).

What do interneurons do?

Integrate information from various sources and send it to motor neurons.

What is the function of motor neurons?

To convey messages from the CNS to effectors in the periphery.

What are effectors?

Muscles, glands, or organs that carry out actions commanded by motor neurons.

What is a reflex?

An involuntary, unconscious movement in response to a stimulus.

What are the five steps in the pain-withdrawal reflex?

1) Painful stimulus activates a receptor. 2) Signal transmitted to spinal cord by sensory neuron. 3) Signal passed to motor neuron by interneuron. 4) Motor neuron stimulates effector muscle. 5) Effector muscle causes withdrawal response.

What does the peripheral nervous system (PNS) do?

Links the CNS to the body and consists of sensory and motor neurons.

What are the two parts of the motor portion of the PNS?

The somatic nervous system (voluntary responses) and the autonomic nervous system (involuntary responses).

What is the role of the sympathetic division of the autonomic nervous system?

Prepares the body for 'fight or flight' responses.

What is the role of the parasympathetic division of the autonomic nervous system?

Dominates during 'rest and rumination' to conserve energy.

What are the three defenses of the central nervous system (CNS)?

1) Skull and vertebral column, 2) Meninges (three layers of connective tissue), 3) Blood-brain barrier (BBB).

What is the function of cerebrospinal fluid?

Acts as a cushion and nourishes/removes waste from CNS cells.

What is the structure of the spinal cord?

Contains dorsal root (sensory neurons), gray matter (interneurons and motor neurons), white matter (myelinated axons), and ventral root (motor neurons).

What are the three main parts of the brain?

Forebrain, midbrain, and hindbrain.

What is the function of the medulla oblongata?

Controls automatic functions such as breathing, heart rate, and involuntary muscle actions.

What role does the pons play in the nervous system?

Works with the medulla oblongata in autonomic roles and regulates sleep transitions.

What is the cerebellum responsible for?

Coordinating movements, maintaining balance, and motor learning.

What is the reticular formation?

A relay and filtering station in the midbrain for auditory and visual information.

What neurotransmitter is produced in the addiction center of the brain?

Dopamine.

What role does dopamine play in the brain?

It is part of the reward circuit and plays a role in sleep, wakefulness, emotion, and some movements/reflexes.

What are the main components of the forebrain?

The thalamus, hypothalamus, and cerebral cortex (cerebrum).

What is the function of the thalamus?

It channels sensory information (except olfaction) to the limbic system and cerebral cortex.

What is the hypothalamus responsible for?

It coordinates between the nervous system and endocrine system and is responsible for homeostasis.

What is the largest part of the human brain?

The cerebrum (cerebral cortex).

What increases the surface area of the cerebral cortex?

The convolutions (folds) known as fissures or convolutions.

What connects the two hemispheres of the brain?

The corpus callosum.

What are the three small bones in the middle ear called?

The ossicles, which include the malleus, incus, and stapes.

What is the function of the auditory (Eustachian) tube?

It equalizes pressure between the middle ear and the air in the mouth and nose.

What are the three areas of the inner ear?

The vestibule, semicircular canals, and cochlea.

What does the vestibule do?

It establishes head position (static equilibrium) and contains the utricle and saccule.

What is the role of the semicircular canals?

They help identify complex body movements (dynamic equilibrium).

What is the cochlea responsible for?

It is involved in hearing and contains specialized hair cells that respond to sound frequencies and intensities.

How does sound travel through the ear?

Sound waves push against the tympanic membrane, causing it to vibrate and send vibrations to the ossicles.

What happens to sound energy at the oval window?

It is concentrated and amplified as it moves from the larger tympanic membrane to the smaller oval window.

What is the Organ of Corti?

It is composed of rows of specialized hair cells that send auditory information to the brain.

How does the cochlea identify pitch?

Different frequencies activate hair cells at different locations along the cochlea.

What determines the loudness of a sound?

The amplitude of the sound wave; greater amplitude means louder sound.

What can cause the sensation of 'hearing bells' in boxers?

A hard hit to the side of the head can stimulate hair cells in the inner ear.

What is required for sound to travel?

A medium; sound travels fastest through solids, then liquids, and slowest through gases.

What happens when the tympanic membrane vibrates?

It sends vibrations to the ossicles, which amplify the sound.

What is the function of the tiny muscles connected to the ossicles?

They protect against loud noises by restricting the movement of the bones.

What is the role of the round window in the inner ear?

It moves outward in response to the inward push of the oval window, allowing fluid waves to form.

What is the significance of the cochlea's structure?

It allows for the identification of different sound frequencies and intensities.

What happens to sound waves in the cochlea?

They create waves in the fluid, which move the basilar membrane and bend hair cells.

How does the brain interpret sound?

Through the information sent via the auditory nerve from the stimulated hair cells.

What is the tough white outer layer of the eye that maintains the shape of the eye called?

Sclera.

What is the primary function of the sclera?

To protect the eye and maintain its shape.

What is the transparent, bulging front part of the eye?

Cornea.

How does the cornea obtain oxygen?

From the air dissolved in tears.

What is the function of the choroid layer?

To prevent light from scattering and support the eye's structure.

What controls the color of the eyes?

Iris.

What is the role of the lens in the eye?

To focus images onto the retina.

What are ciliary muscles responsible for?

Changing the shape of the lens for focusing.

What is the vitreous humour?

A jelly-like substance that helps maintain the shape of the eyeball.

What are the two types of light-sensitive cells in the retina?

Rods and cones.

What do rods in the retina allow us to see?

Black and white in low light conditions.

What do cones in the retina allow us to see?

Color in high light conditions.

What is the fovea centralis?

The area of highest visual acuity in the retina.

What is the blind spot in the eye?

The area where the optic nerve connects to the retina, lacking rods and cones.

What is accommodation in the context of vision?

The adjustment of the lens shape to focus on objects at different distances.

What causes color blindness?

Defective cones, particularly red cones in red-green color blindness.

What is hyperopia?

Farsightedness, where distant objects are seen clearly but close objects are blurry.

What is myopia?

Nearsightedness, where close objects are seen clearly but distant objects are blurry.

What is glaucoma?

A condition caused by increased pressure in the eye due to fluid build-up.

What are cataracts?

A condition where the lens becomes opaque, blocking light.

What is astigmatism?

A vision condition caused by an irregularly shaped lens or cornea.

What are olfactory receptors responsible for?

Detecting airborne chemicals for the sense of smell.

What are the five major types of taste receptors?

Sweet, salty, sour, bitter, and umami.

What triggers pain receptors in the body?

Damaged cells releasing potassium ions and bradykinin.

What is echolocation?

A navigation method used by some animals to detect prey in the dark.

What is electrolocation?

The detection of electrical fields used by certain animals for communication and hunting.