Physiological Psychology Lab Exam 1

Two division of the nervous system

• Central Nervous System/CNS

• Peripheral Nervous System/PNS

Central Nervous System

brain and spinal cord

Peripheral Nervous System

all the nerves outside of the brain and spinal cord

Division of the peripheral nervous system

• Somatic

• Autonomic

Somatic Nervous System

controls voluntary body movements and processes incoming sensory information from the skin, muscles, joints, etc.

Autonomic Nervous System

regulates involuntary physiological processes of the body, such as heart rate, blood pressure, digestion, respiration, etc.

Parts of the autonomic nervous system

Sympathetic and Parasympathetic

Sympathetic Division

division of the peripheral nervous system that controls the “fight or flight” response

Parasympathetic Division

division of the peripheral nervous system that helps the body relax and conserve energy, referred to as “rest and digest”

Efferent Neurons

motor neurons that carry information from the brain to the rest of the body

Afferent Neurons

sensory neurons that carry sensory information from the body to the brain.

Blood-Brain Barrier

protects the CNS from harmful substances entering the brain or spinal cord from the blood in our body

Meninges and Bones

help to protect the CNS

Hindbrain Divisions

Myelencephalon and Metencephalon

Hindbrain Structures

Medulla, Pons, Cerebellum

Myelencephalon

division of the hindbrain that includes the medulla

Metencephalon

division of the hindbrain that includes the pons and cerebellum

Midbrain Division

Mesencephalon

Midbrain Structures

Tectum and Tegmentum

Mescencephalon

division of the midbrain including the tectum and tegmentum

Forebrain Divisions

Diencephalon and Telencephalon

Forebrain Structures

• Thalamus

• Hypothalamus

• Cerebral Cortex

• Basal Ganglia

• Hippocampus

• Amygdala

Diencephalon

division of the forebrain that includes the thalamus and hypothalamus

Telencephalon

division of the forebrain that includes the cerebral cortex, basal ganglia, hippocampus, and amygdala

Four Cortical Lobes of the Brain

frontal, temporal, occipital, and parietal

Frontal Lobe

one of the cortical lobes that contains:

• Frontal and motor cortices

• Superior, Middle, Inferior Gyri

• Central Sulcus

Precentral Gyrus

motor cortex

Postcentralm Gyrus

somatosensory cortex

Parietal Lobe

one of the cortical lobes that contains:

• Superior Parietal Lobule

• Inferior Parietal Lobule

Occiptial Lobe

one of the cortical lobes that contains:

• Parieto-occipital sulcus

• Calcarine fissure

• Cuneus

Temporal Lobe

one of the cortical lobes that contains:

• Lateral Sulcus

• Superior or Temporal Gyrus

• Middle Temporal Gyrus

• Inferior Temporal Gyrus

Order of the Meninges

Dura Mater (closest to the outside, skull) —> Arachnoid Mater —> Pia Mater (closest to the inside, brain)

Neurons

functional cellular unit of the nervous system that transmits information via action potentials and neurochemical release

Glia

provide structural and metabolic support for neurons (modulate, support, insulate, etc.)

Glia of the CNS

Oligodendrocytes and Ependymal

Glia of the PNS

Schwann and Satelite Cells

Glia of both the CNS and PNS

Astrocytes and Microglia

Macroglia

glial cell type containing astrocytes, oligodendrocyte, schwann cells, and staelite cells

Astrocyte

macroglia cell of the CNS and PNS that provides physical and nutritional support to neurons

Oligodendrocyte

macroglia cell of the CNS that forms Myelin sheaths and provides guidance

Schwann Cell

macroglia cell of the PNS that forms myelin sheaths and provides guidance

Satelite Cell

macroglia cell of the PNS that provides physical support to neurons

Ependymal

type of glial cell found in the CNS that lines the ventricles

Microglia

type of glia cell found in the CNS and PNS that is responsible for tissue repair, debris removal, and defense

Grey Matter

divided into “horns” (dorsal and ventral); some axons but mostly cell bodies

White Matter

composed of only myelinated axons, surrounds central grey matter

Ways to Classify Neurons

• Based on the number of extensions that extend from the neuron’s soma

  • Unipolar - touch, pain neurons

  • Bipolar - vision, hearing neurons

  • Multi-polar - Most neurons in the brain

• According to their connections

  • Sensory (afferent) and Motor (efferent) (reside partly in CNS and PNS)

  • Interneurons (local info) and Projection neurons (reside entirely in the CNS)

Coronal Section

divides the brain into dorsal and ventral sections

Sagittal Section

vertical plane that divides the brain into left and right sections

Horizontal Section

horizontal plane that divides the brain into upper and lower sections.

Human Brain Orientation

Sheep Brain Orientation

Focus on anterior and posterior rather than rostral and caudal since we are using sheep brains

Why does the orientation of the CNS change moving from the spinal cord to the brain in humans?

the evolution of bipedalism requires a different spatial understanding for human brains versus the brain of an animal that moves on all fours.

Cortical Folding

creates “hills” (gyri) and “valleys” (sulci) on the surface of the brain to increase cortical surface area in more advanced organisms, allowing for more complex processes.

Lissencephalic

smooth brain

Ventricles

contain cerebral spinal fluid

Different types of ventricles

• Lateral Ventricles

• Third Ventricle

• Cerebral Aqueduct

• Fourth Ventricle

• Central Canal

Steps in Histological Preparation of Tissue

1. Fixing

2. Processing

3. Embedding

4. Slicing

5. Staining

Fixation

1. Blood is drained from the body (by means of saline)

2. Fixative solution (usually formalin) is pumped into vascular system to replace remaining fluid

3. Stabilize tissue, disable intrinsic molecules and enzymes to prevent degredation, and increase tissue strength for further processing

Processing

1. Embedding in paraffin/ wax (microtome), or

2. Treatment with sugars to prevent cell damage during freezing (cryostat)

3. Does not occur when using a vibratome and is optional with the cryostat

Slicing

1. VIbratome, can section unprocesed tissue

2. Cryostat is relatively fast and does not require embedding

3. Microtome provides high quality for thin sections/high mag resolution

Staining

1. Nissl stain provides good general tissue contrast, stains cell bodies (nissl)

2. Myelin stains affect white-matter only (luxol blue)

3. Golgi/Silver stains highlight just a few neurons in full detail

Cresyl Violet Nissl Staining Method

• Hydration helps the stain fix in the tissue because cell bodies are full of water

• Dehydration with ethanol solutions help differentiate the Nissl stain by decoloring high myelinated areas of the brain

  • Dehydration if done from less (70%) to more concentrated (100%) to avoid damaging the tissue due to dramatic changes in the environment where the tissue was previously exposed (distilled water and cresyl violet)

Epidural Space

Area between the periosteum of the spinal column and the dura mater of the spinal cord containing mostly adipose tissue.

Subarachnoid Space

space between the arachnoid mater and pia mater of the spinal cord that contains cerebrospinal fluid.

Anasthesia in the Subarachnoid Space

• Considered more dangerous due to punturing the meninges around the spinal cord

• More widespread effect due to the circulating CSF

• Can cause headaches in patients after waking up due to the circulation of the CSF

Anasthesia in the Epidural Space

• Considered safer since the meninges of the spinal cord are not punctured

• More of a local anasthetic, can pinpoint the exact nerves you want to target and select where to do the injection along the spinal column

Cevical Vertebrae

8 (C1 - C8). Generally involved with the head, neck, shoulders, diaphragm, radial side of arm, and hands.

Thoracic Vertebrae

12 (T1 - T12). Generally involved with the trunk, muscles, chest wall, organs, and ulnar side of the arm.

Lumbar Vertebrae

5 (L1 - L5). Generally involved with lower back, legs, and feet.

Sacral Vertebrae

5 (S1 - S5). Generally involved with bowel, bladder, sexual functions, and heels.

Coccygeal Vertebrae

only 1 at the coccyx

Complete Spinal Cord Injury

no movement or sensation below injury

Incomplete Spinal Cord Injury

partial damage to cord (movement/no sensation or vice versa)

Hangman’s Fracture

spinal cord injury at C2; usually fatal due to brain stem injury (medulla)

SCI below brainstem, but above C3, C4, C5

usually leads to asphyxiation

Quadriplegia

loss of feeling in most of the body

Paraplegia

loss of lower extremities

SCI between C1 and C5

paralysis of some or all muscles used for breathing and all arm and leg muscles. Typically, fatal unless ventillator is used.

SCI between C5 and C6

Paralysis of the legs, trunk, hands, wrists. Weakness of the muscles that move the shoulder and elbow.

SCI between C6 and C7

paralysis of the legs, trunk, and part of the wrists and hands. Normal movement of the shoulders and elbows.

SCI between C7 and C8

Paralysis of the lefs, trunk, and hands

SCI between C8 and T1

Paralysis of the legs and trunk. Weakness of the muscles that move fingers and hands. Horner’s syndrome (drooping eyelid, constricted pupil, and reduced sweating on one side of the face). Possibly normal movement of shoulders and elbows.

SCI between T2 and T4

paralysis of the legs and trunk. Loss of sensation below the nipples. Normal movement of the shoulders and elbows

SCI between T5 and T8

paralysis of the legs and lower trunk. Loss of sensation below the rib cage

SCI between T9 and T11

paralysis of the legs. loss of sensation below the navel.

SCI between T11 and L1

paralysis of and loss of sensation in the hips and legs

SCI between L2 and S2

various patterns of leg weakness and numbness, depending on the prcise level of injury

SCI between S3 and S5

numbness in the perineum

A severe injury at any level of the spinal cord can

cause loss of bladder and bowel control

Dermatome

an area of skin/the body associated with a single spinal cord segment (sensory and motor region)

Decussation

the crossing of two things, usually in the form of an X.

Pyramidal Decussation

when motor fibers pass from the brain to the medulla spinalis and medulla oblongata

Dorsal Root

sensory axons and interneuron cell bodies, ascending

Ventral Root

motor cell bodies, descending

Horns

present in gray matter and divided into dorsal and ventral

Multiple Sclerosis (MS)

preferentially affects cervical spinal cord (dorsal areas). Body’s immune cells attacking myelin leading to inflammation around nerves. Symptoms include:

• Ascending numbness, starting in feet

• Bilateral hand numbness

• Numbness on one side of the body

Amyotrophic Lateral Sclerosis (ALS)

• Loss of lower motor neurons in the ventral horn

• Degredation of lateral column pathways in spinal cord

• Muscle atrophy

• No changes in intellect or memory

Meningitis

Inflammation of the meninges leading to headache, stiff neck, high fever. Massive immune response in the CNS leads to swelling and cell death. Detected through spinal tap to check for bacteria in CSF. Also referred to as “Dorm Disease”

Encephalitis

a serious brain inflammation that can occur due to an infection or autoimmune resonse. Can create a variety of symptoms, including headaches, seizures, and confusion. In severe cases can lead to brain damage, stroke, or death.