Lecture 8: Sensory Systems - Neuronal Organization and the Brain

Question 1

Central Nervous System

Answer 1

CNS
Made up of brain and spinal cord
Covered with 3 protective layers called meninges.

Question 2

Dura Mater

Answer 2

The outermost layer
Protects the brain and spinal cord
Contains Vein like structures that carry blood from the brain back to the heart

Question 3

Arachnoid Mater

Answer 3

The middle layer

Question 4

Pia Mater

Answer 4

The last, innermost layer
It directly contacts and covers the brain and spinal cord

Question 5

Cerebrospinal fluid

Answer 5

Space between arachnoid and Pia mater
Produced by choroid plexus in ventricles
Acts as cushion and shock absorber and makes the brain neutrally buoyant
Functions to circulate chemical substances throughout the brain and spinal cord

Question 6

Hydrocephalus

Answer 6

Swelling which causes the brain to be pushed back against the skull
As a result of constant production of CSF in ventricles which eventually blocks the ventricles and CSF builds up
May cause seizures, cognitive problems

Question 7

Autonomic Nervous System

Answer 7

Serves as the relay between the CNS and the internal organs
Controls the lungs, the heart, smooth muscle, and exocrine and endocrine glands.
Controls largely without conscious control
Usually involves 2 synapses: a preganglionic neuron synapses to a neuron in a ganglion that synapses on the target organ
Made up of 2 divisions: Sympathetic and Parasympathetic nervous systems

Question 8

Sympathetic Nervous System

Answer 8

Responsible for the “fight or flight” response that occurs when an animal encounters a dangerous situation.
Examples are accelerated heart rate and inhibited digestion
Help prepare an organism’s body for the physical strain required to escape a potentially dangerous situation.

Question 9

Parasympathetic Nervous System

Answer 9

Allow animal to “rest or digest”
Resets organ function after sympathetic nervous system is activated.

Question 10

Sensory-somatic nervous system

Answer 10

Made up of cranial and spinal nerves and contains both sensory and motor neurons

Question 11

Sensory Neurons

Answer 11

Transmit sensory information from the skin, skeletal muscle, and sensory organs to the CNS.
Have cell bodies which are grouped in dorsal root ganglia
Has one projection with a sensory receptor ending in the skin, muscle, or sensory organs and another which synapses with a neuron in the dorsal spinal cord.

Question 12

Motor Neurons

Answer 12

Transmit messages about the desired movement from the CNS to the muscles to make them contract.
Have cell bodies in the ventral gray matter of the spinal cord that project to muscle through ventral root

Question 13

Cranial Nerves

Answer 13

Nerves that emerge from or enter the skull
Humans have 12
Some transmit only sensory information (Olfactory Nerve) while some others transmit solely motor information (Oculomotor nerve) and some have a mix of both (Glossopharyngeal nerve)

Question 14

Spinal Nerves

Answer 14

Nerves that emerge from the vertebral column.
Transmit sensory and motor information between the spinal cord and the rest of the body.
Humans have 31 (All contain both sensory and motor axons)

Question 15

Peripheral Nervous System

Answer 15

Contains both the autonomic and sensory-somatic nervous system.

Question 16

Glia

Answer 16

Cells that provide support functions for the neurons by playing an information processing role that is complementary to neurons.

Question 17

Brain

Answer 17

Part of the central nervous system that is contained in the cranial cavity of the skull.
Includes cerebral cortex, limbic system, basal ganglia, thalamus, hypothalamus, and cerebellum.

Question 18

Cerebral cortex

Answer 18

The outermost part of the brain
Thick piece of nervous system tissue.
Folded into hills called gyri and valleys called sulci.
Made up of right and left hemisphere separated by a large sulcus.

Question 19

Corpus Callosum

Answer 19

Thick fibre bundle which connects the two hemispheres and allows information to be passed from one side to the other.

Question 20

Lobes of the hemispheres of the brain

Answer 20

Frontal Lobe
Parietal Lobe
Temporal Lobe
Occipital Lobe

Question 21

Frontal Lobe

Answer 21

Located at the front of the brain, over the eyes.
Controls the olfactory bulb (Processes smells)
Contains the motor cortex (Important for planning and implementing movement)
Control cognitive function such as maintaining attention, speech and decision-making.

Question 22

Parietal Lobe

Answer 22

Located at the top of the brain
Neurons are involved in speech and reading.
Somatosensation: Touch sensations like pressure, pain, heat or cold
Proprioception: The sense of how parts of the body are oriented in space
Contains a somatosensory map of the body

Question 23

Occipital Lobe

Answer 23

Located at the back of the brain
Primarily involved in vision-seeing, recognizing and identifying the visual world.

Question 24

Temporal Lobe

Answer 24

Located at the base of the brain by ears
Involved in processing and interpreting sounds.
Contains the hippocampus, a structure that process memory formation.

Question 25

Basal Ganglia

Answer 25

Interconnected brain areas which play important roles in movement control and posture

Question 26

Thalamus

Answer 26

Acts as a gateway to and from the cortex.
Receives sensory and motor inputs from the body and also receives feedback from the cortex.
Helps regulate consciousness, arousal and sleep states.

Question 27

Hypothalamus

Answer 27

Controls the endocrine system by sending signals to the pituitary gland (a small gland which releases hormones that affects other glands as well)
Regulates important behaviours that are controlled by such hormones.
Body’s thermostat
Neurons regulate circadian rhythms

Question 28

Limbic System

Answer 28

Connected set of structures that regulates emotion and behaviours related to fear and motivation.
Plays a role in memory formation
Includes parts of the thalamus, hypothalamus, and hippocampus.
Has the amygdala: Important for the sensation of fear and recognizing fearful faces.
Has cingulate gyrus: Helps regulate emotions and pain

Question 29

Cerebellum

Answer 29

Sits at the base of the brain, on top of the brainstem.
Controls balance and aids in coordinating movement and learning new motor tasks.

Question 30

Brainstem

Answer 30

Connects the rest of the brain with the spinal cord.
Consists of the midbrain, medulla oblongata, and the pons.
Coordinates motor control signals sent from the brain to the body
Controls alertness, arousal, breathing, blood pressure, digestion, heart rate, swallowing, walking, and sensory and motor information integration.

Question 31

Spinal Cord

Answer 31

Thick bundle of nervous tissue that carries information about the body to the brain and from the brain to the body.
Contained within the bones of the vertebrate column
Controls motor reflexes

Question 32

Gray Matter

Answer 32

Made up of glial cells
Composed of interneurons (They connect 2 neurons each located in different parts of the body)