Lecture 14: Nervous System + Brain PT 1 Flashcards
What is the role of the nervous system?
Regulates bodily functions and maintains homeostasis
Also assisted by the endocrine system for hormonal responses.
What are the basic functions of the nervous system:
Sensory Function- Sense changes in the external and internal environments which are detected through the sensory receptors (afferent)
Integrative Function- Sensory information is processed, and makes decisions regarding appropriate responses. (Association or interneurons)
Motor Function- Responds to stimuli initiating action through motor neurons (efferent)
Organize the nervous system.
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Central Nervous System (CNS) - Made up of brain and spinal chord
- Peripheral Nervous System (PNS)- Made up of Cranial, spinal nerves, ganglions, plexuses and sensory receptors.
Outline the flow of electrical signals throughout the body when detected.
- Special and Somatic senses (sensory input) → Sends information to CNS FOR INTEGRATION → CNS then sends signals to motor output → Somatic nervous system (skeletal muscles), Autonomic Nervous system
AUTONOMIC FURTHER DIVIDES AS SYMPATHETIC (SMOOTH MUSCLE), PARASYMPATHETIC (HEART MUSCLE) ENTERIC (SMOOTH AND DIGESTIVE MUSCLES)
What are the functional units of the nervous system, and what is its role
Neurons- Propagate electrical impulses (MAIN FUNCTIONAL UNIT)
Neuroglia- Supportive cell
Describe the main parts of the neuron and what their functions are.
- Dendrite- Reception of electrical impulses from other neurons or sensory inputs. NOT MYELINATED
- Cell Body - Integrates electrical signals
- Axons- Propagates electrical signals from neuron to neuron, terminal branches make synaptic contacts.
What is a synapse and what does it create?
A synapse is a junction between either 2 neurons or a neuron to an effector organ.
When a nerve impulse reaches the axon terminal, a **postsynaptic potential is created for either an excitatory or inhibitory response which will create a secondary nerve impulse. **
Identify and describe the features of the 3 types of neurons.
- Multipolar neuron- One structure coming of cell body
- Bipolar neuron- 2 structures coming of cell body
- Unipolar neuron- axon and dendrites are fused.
1.
What are the neuroglial cells in the PERIPHERAL nervous system?
Schwann Cells- Myelin production (wraps around the axon of neuron)
Satellite Cells- Regulation of chemical external environment
What are the neuroglial cells in the CNS.
Oligodendrocytes → Myelin Productions for neurons in the PNS
Astrocytes→ Structural support and regulation of metabolic exchange
Microglia- Macrophage activity neuronal immune defence
Ependymal Cells- Produces and circulates cerebral spinal fluid
What are the meninges in your brain?
- Dura Mater
- Arachnoid Mater
- Pia Mater
What is the dura mater made of? Classify the types of Dura.
The dura mater is made out of dense irregular CT (most superficial)
- Cranial Dura : 2 Layers, No epidural space
- Dural Folds: 1) Falx Cerebri - Separates 2 hemispheres
- 2) - Falx Cerebelli - Separates hemispheres of cerebellum
- 3) Tentorium Cerebelli - Separates cerebellum and cerebrum
- Venous Sinuses (drainage of blood from dura)
Spinal Dura: 1 Layer, epidural space between spinal chord and vertebra
What is the middle layer of the meninges called, describe its key features.
ARACHNOID MATER- transparent middle layer, avascular
- Has a subdural space (below dura) which contains interstitial fluid
- Arachnoid villi which protrudes into dura venous sinus.
What is the innermost layer of the meninges? Describe it.
Pia Mater: Well vascularised
- Subarachnoid space which contains cerebrospinal fluid.
- Spinal Pia has LATERAL EXTENSIONS of thickened pia called DENTICULATE LIGAMENTS which protect and anchor spinal chord.
What is cerebrospinal fluid? Identify its function and where it is produced.
CSF is mainly water and contains o2, glucose and some WBC
Function- Protection and circulation of fluids
Circulates throughout the brain and spinal chord through the subarachnoid space and cavities in the brain called ventricles.
PRODUCED IN THE CHOROID PLEXUSES (located in individual ventricles ie, right lateral ventricle, 3rd and 4th ventricle.
Identify the lobes of the brain:
- Frontal Lobe: has the central sulcus and the precentral gyrus.
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Parietal Lobe: Postcentral gyrus
- Temporal Lobe: Lateral Sulcus
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Occipital Lobe:
- Insula: within lateral sulcus and deep to temporal parietal and frontal lobe.
What is white matter made of? Identify its main communication methods.
White matter is innermost to the grey matter in charge of coordination of information from different regions in the brain and is made out of myelinated axons, existing in 3 tracts.
- Association (communication between lobes and gyri of the same hemisphere)
- Commissural (btwn hemispheres) → corpus callosum, anterior commissure and posterior commissure
- Projection → cerebrum to the rest of the body
