Neuro Ex Exam 1

Neuroanatomy and History of Neuroscience and Exercise

Costs associated with lack of physical activity

$300 billion worldwide, $117 million in the US

when was exercise first prescribed as medicine and by whom?

600 BCE by Sushruta

What are the leading causes of death in the US?

heart disease, cancer, unintentional accidents, and lower respiratory disease

What proportion of adults are physically inactive?

25.3%

Naturals

things with nature, are innate/have genetic predisposition

Non-naturals

things not innate, a person has some control

ex: air quality

contra-naturals

things that are against nature (pathologies)

List parts of a neuron (in order of action potential)

Dendrites, soma (cell body), axon hillock, axon proper, axon terminal

Microtubules in Neurons

run along neurites (axons and dendrites)

Neurofilaments in Neurons

neuronal skeleton

microfilaments in neurons

change cell shape

Three types of neuron classification

1. Number of neurites (dendrites + axon)

2. connections/info transmission

3. axon length

Unipolar Neuron

1 neurite

Bipolar Neuron

2 neurites

Multipolar neuron

more than 3 neurites; primary in the brain

primary sensory neuron

afferent

primary motor neuron

efferent

interneurons

connect efferent and afferent neurons

Golgi Type 1 Neurons

long axon from one part of the brain to another

Golgi Type 2 Neurons

short axons that don’t extend beyond the cell body (local circuit neurons)

Glia

provide metabolic and functional support for neurons

Types of macroglia

1. oligodendrocytes (CNS)

2. Schwann Cells (PNS)

3. Astrocytes

Astrocytes

regulate chemical content of extracellular space and act as scaffolding for growing neurons

Both oligodendrocytes and schwann cells:

axon insulation, form myelin sheath

Microglia/Phagocytes

promote tissue repair and remove degenerating neurons; assist with remodeling synaptic connections

Neurotransmitters

chemical messengers that carry signals between nerve cells; peptides or amino acids

What are neurotransmitters directly involved in?

signal transmission across the synaptic cleft

Central Nervous System

brain and spinal cord

Peripheral Nervous System

everything besides the brain and spinal cord; autonomic and somatic

divisions of the autonomic nervous system

sympathetic (EPI) and parasympathetic (ACH)

Parasympathetic Hormone

acetylcholine

Sympathetic hormone

epinephrine (adrenaline)

Rostral

towards nose/frontal lobe

Caudal

tail side

Dorsal

top

ventral

under side of brain

coronal section

vertical

axial section

horizontal, should be able to see the eyes

Midsagittal

direct midline of the brain, splits into hemispheres

Parasagittal

splits brain into uneven hemispheres

Tel - Di - Mes - Met - My

brain subdivisions, top → down

cortices (sg. cortex)

flattened sheets of neurons

nuclei

3D configurations of neurons

Medulla Oblongata Function

• sensory and motor innervation

• heart rate, respiration, decussation

Medulla Oblongata Location

brain stem/myelencephalon

How many of the 12 cranial nerves does the medulla house?

7

Pons Function

decussation

Pons Location

Brain stem/metencephalon

Cerebellum Function (Bring Plates, Linens, And Lobster)

• body position (decussation)

• balance (vestibular, visual, auditory inputs)

• ambulation/locomotion

• language, attention, learning, mental imagery

Cerebellum Location

brain stem/metencephalon

Decussation

where afferent and efferent meet and exchange information

Midbrain Location

mesencephalon

Midbrain Function (Midlothian, VA)

• cranial nerves 3 and 4

• vision (superior) and auditory (inferior)

subsections of the midbrain

• superior colliculus

• inferior colliculus

Thalamus Location

diencephalon

Thalamus Function

all sensory and motor information goes through it

• motor output and sensory input

Hypothalamus Location

projects into prefrontal cortex, amygdala, spinal cord, and pituitary

Hypothalamus Functions (Double H)

• limbic system input

• homeostasis + circadian rhythms

• produces/regulates hormones

How do you know if hormones came from the hypothalamus?

they are a releasing hormone

Pituitary Gland Location

top of spinal cord, below hypothalamus

Pituitary Gland Functions

hormone release

Pituitary Structure

• layers like an onion, each for a different hormone

• connected to the hypothalamus via the infundibulum

• adenohypophysis and neurohypophysis

Infundibulum

connects pituitary gland to the hypothalamus; onion’s stem

Adenohypophysis

rostral, towards eyes

Neurohypophysis

caudal, towards occipital lobe

Pathway of stimulus to response (reflex)

1. sensory neuron (afferent)

2. received in ventral root of spine

3. motor output sent out of dorsal root of spine

4. motor neuron (efferent)

Pathway of stimulus to response (non-reflex)

1. sensory neuron (afferent)

2. dorsal nerve root

3. spinal cord

4. medulla

5. pons

6. thalamus

7. prefrontal cortex

8. primary motor cortex

9. primary somatosensory cortex

10. back down from thalamus to efferent

What makes up the limbic system?

• Basal Ganglia

• Hippocampus

• Amygdala

Limbic System

organized “emotion” system

Basal Ganglia - Librarian

collection of interconnected nuclei (sorts info)

Basal Ganglia Function (pneumonic PGR)

• action selection/gating

• motor preparation and timing

• reward-based learning

Hippocampus - bookshelves

recipient of highly processed information

Subsections of the hippocampus (Does George See His Past?)

• dentate gyrus

• subiculum

• hippocampus proper

Hippocampus Function

memory consolidation (declarative and spatial)

Amygdala - customer

recipient of sensory + cognitive information

Amygdala Functions

• emotional content of an experience

• implicated in depression, anxiety, and substance abuse

Sulci

crevices; canyons of the cerebral cortex

Gyri

crowns; hills of cerebral cortex

Advantages of Sulci + Gyri

allow short distances for transmission and a greater surface area at the same time

Frontal Lobe

planning + execution of actions

Parietal Lobe

sensory

Temporal Lobe

auditory, visual, multimodal processing

Occipital

primarily visual information

Prefrontal Cortex

planning and organization

Primary Motor Cortex

plan execution

Primary Somatosensory Cortex (4) (To Pass, Turn Left)

touch, pain, temperature sense, limb proprioception

Homunculus Example

popcorn stuck in the teeth, tongue is a neurosurgeon

Reticular Formation

activates limbic system

Ratio of glucose to oxygen

1:6

Ratio of oxygen to ATP

5.7:1

Glycolysis

breaking down of glucose into acetyl COA and ATP

Brain Glycogen

broken down to glucose for energy in the brain

What proportion of glycogen needed by the brain is stored in astrocytes (macro)?

5-15%

what are synaptic “rich” areas? (7)

• grey matter

• medulla

• pons

• cerebellum

• hypothalamus

• cortex

• striatum

how much glycogen does grey matter need compared to white matter?

2 times

Partial pressure (amount) of CO2 in the blood (PaCO2)

a measure of how much CO2 is in the blood

How does exercise affect mean arterial pressure (MAP)?

increases MAP

Effects of moderate exercise on PaCO2

• increased PaCO2

• increased middle cerebral artery (MCA) velocity

• increased O2 flow

• increased removal of toxins

Effects of strenuous exercise on PaCO2

• reduction of PaCO2

• decreased MCA velocity

• decreased arterial oxygenation

• decreased pH

• decreased O2 flow

Why is strenuous exercise bad for PaCO2 and MCA velocity?

it’s not sustainable long term and can be detrimental to the body (only goal is trying to survive)