Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
HHIS
NERVOUS TISSUE and NERVOUS SYSTEM (PART 1)
| Question | Answer |
|---|---|
| NERVOUS SYSTEM | The MOST COMPLEX SYSTEM in the body |
| NERVOUS SYSTEM | Formed by a network of many billion nerve cells (neurons), all assisted by many more supporting cells (glial cells) |
| NERVOUS SYSTEM | The nervous tissue is distributed throughout the body as an integrated communications network |
| 2 GENERAL DIVISIONS: | Central Nervous System (CNS) Peripheral Nervous System (PNS) |
| Central Nervous System (CNS) | Brain Spinal cord |
| Peripheral Nervous System (PNS) | Cranial Nerves Spinal nerves Peripheral nerves Gangglia |
| DEVELOPMENT OF NERVE TISSUE | The nervous system develops from the outermost of the 3 embryonic layer (ECTODERM), beginning in the 3rd week of development |
| DEVELOPMENT OF NERVE TISSUE (The process is termed as) | NEUROLATION |
| SENSORY DIVISION | SOMATIC VISCERAL |
| SOMATIC | sensory input perceived consciously (eyes, ears, skins, muscular) |
| VISCERAL | sensory input that are not perceived consciously (internal organs, cardiovascular structure) |
| MOTOR DIVISION (EFFERENT) | A.SOMATIC: motor output controlled consciously or voluntarily (skeletal msucle effectors) B.AUTONOMIC: motor output not controlled consciously (heart or gland effectors |
| AUTONOMIC NERVOUS SYSTEM | PARASYMPATHETIC DIVISION SYMPATHETIC DIVISION |
| PARASYMPATHETIC DIVISION | Gangglia within or near the effector organs-an organ, such as muscle or gland, that responds to neural stimulation by producing a particularr response. Maintains normal body homeostasis |
| B.SYMPATHETIC DIVISION | Gangglia close to the CNS Controls the body’s responses during emergencies and excitement. |
| NEURONS Also known as | NERVE CELLS |
| NEURONS | Structural and functional unit of the nervous system |
| NEURONS 3 MAIN PARTS: | CELL BODY (SOMA OR PERIKARYON) DENDRITES AXON |
| CELL BODY (SOMA OR PERIKARYON) | Contains the nucleus and most of the cell’s organs |
| CELL BODY (SOMA OR PERIKARYON) | Serves as the synthetic or trophic (nutritive) center for the entire neuron |
| CELL BODY (SOMA OR PERIKARYON) | Genetics center of a neuron |
| NUCLEUS | spherical or oval, usually large, pale staining (purple), centrally located with a prominent nuclelous |
| CYTOPLASM | ontains Niss’I granules (NissL substance, Nissl bodies, Chromatophilic substance)- basophilic granules due to the abundance of granular reticulum and ribosomes in the cytoplasm: main site of protein synthesis in the nueronal cytoplasm. |
| DENDRITES ETYMOLOGY | “DENDRON” - Tree |
| DENDRITES | Numerous elongated short processes extending from the perikaryon and specialized to receive stimuli from the environment, from the sensory epithelial cells or from other neurons at unique sites called synapses |
| DENDRITES | Principal signal reception and processing sites on neurons |
| DENDRITES | 200,000 axonal endings can make functional contact with the dendrites of a single large Purkinje cell of the cerebellum |
| DENDRITES | Dendrites become much thinner as they branch |
| DENDRITES | Nissl granules extend into the dendrites |
| AXON ETYMOLOGY | “AXON” - Axis |
| AXON | Single long process ending at synapses specialized to: generate and conduct nerve impulses to other cells |
| AXON | Most neurons have only one axon, typically longer than its dendrites |
| AXON | Axons may also receive information from other neurons |
| AXON | Axons originate from a pyramid-shaped region of the perikaryon called: AXON HILLOCK |
| AXON PLASMA MEMBRANE OF AXON | AXOLEMMA |
| AXON CONTENTS OF AN AXON | AXOPLASM |
| STRUCTURAL CLASSES OF NEURONS | PSEUDOUNIPOLAR BIPOLAR MULTIPOLAR ANAXONIC |
| PSEUDOUNIPOLAR Also known as | UNIPOLAR NEURONS |
| PSEUDOUNIPOLAR | Single process close to the perikaryon but divides into 2 branches, with the longer branch extending to a peripheral ending and the other toward the CNS |
| PSEUDOUNIPOLAR EXAMPLES | Cerebrospinal ganglia |
| BIPOLAR | Has 2 processes, consisting of a single dendrite and a single axon |
| BIPOLAR EXAMPLES | Retina Olfactory epithelium Spiral/cochlea of the inner ear Vestibular ganglia of the inner ear |
| MULTIPOLAR | More than 2 processes With one axon and two or more dendrites |
| MULTIPOLAR | MOST COMMON |
| MULTIPOLAR EXAMPLES | Motor neurons of CNS Peripheral autonomic ganglia |
| ANAXONIC | found only in certain CNS interneurons |
| ANAXONIC | lack true axons , do not produce action potentials |
| ANAXONIC | regulate local electrical changes of adjacent neurons. |
| TYPES OF NEURON ACCORDING TO FUNCTION | SENSORY NEURONS MOTOR NEURONS INTER-NEURONS |
| SENSORY NEURONS Also known as | AFFERENT NEURONS |
| SENSORY NEURONS | Involved in: transmission of sensory stimuli from the environment or within the body |
| SENSORY NEURONS | Transmits impulses to the CNS |
| MOTOR NEURONS Also known as | EFFERENT NEURONS |
| MOTOR NEURONS | Transmits impulses from: the CNS to the effector organs (skeletal muscle) or from other efferent neurons that ultimately supply the effectors (smooth muscles, cardiac muscles, and glands) |
| INTER-NEURONS Associated neurons that | transmit impulses from one part of CNS to another |
| INTER-NEURONS | Their processes do not leave the CNS |
| SYNAPSES | Are sites where nerve impulses are transmitted from one neuron to another, or from neurons and other effector cells |
| SYNAPSES | Its structure ensures that the transmission is unidirectional |
| SYNAPSES | Synapses convert an electrical signal (nerve impulse) from the presynaptic cell into a chemical signal that affects the post-synaptic cell |
| SYNAPSES | Most synapses act by: releasing neurotransmitters- which are usually small molecules bind specific receptor proteins to either open or close ion channels or initiate second messenger cascades |
| SYNAPSES | Area of contact of one axon with the dendrites or perikaryon of another that possess polarity |
| PRE-SYNAPTIC AXON TERMINAL Also known | TELEDENDRON MEMBRANE OR TERMINAL BOUTON |
| PRE-SYNAPTIC AXON TERMINAL | Contains synaptic vesicles from which neurotransmitter is released by: EXOCYTOSIS |
| SYNAPTIC CLEFT Also known as: | SYNAPTIC GAP |
| SYNAPTIC CLEFT | 20-30 nm wide intercellular space that separates the pre-synaptic and post-synaptic membranes |
| POST-SYNAPTIC CELL MEMBRANE | Contains receptors for the neurotransmitter, and ion channels or other mechanisms to initiate a new impulse |
| TYPES OF SYNAPSES | 1.AXOSOMATIC SYNAPSE 2.AXODENDRITIC SYNAPSE 3.AXOAXONIC SYNAPSE: axons to axons |
| GLIAL/NEUROGLIAL CELLS | Supporting cells of the CNS Support neuronal survival and activities |
| GLIAL/NEUROGLIAL CELLS | They do not synapse with each other On H and E stain, only the nuclei are seen while the cytoplasm and processes of the neuroglia are not visible (HEMATOXYLIN AND EOSIN |
| NEUROGLIAL CELLS OF THE CNS | ASTROCYTES OLIGODENDROCYTES MICROGLIAL CELLS EPENDYMAL CELLS |
| ASTROCYTES ETYMOLOGY | “ASTRO”- Star “KYTOS”- Cells |
| ASTROCYTES | Most important supporting cell if the CNS Most numerous glial cells of the brain |
| ASTROCYTES | Nucleus is spherical, centrally located and pale staining Have large numbers of long radiating, branching processes |
| ASTROCYTES FUNCTIONS | Help keep the blood brain barrier Regulates interstitial fluid composition |
| ASTROCYTES FUNCTIONS | rovides structural support and organization to the CNS Assist with neuronal development Replicates to occupy spaces of ding neurons |
| ASTROCYTES TYPES | FIBROUS ASTROCYTES PROTOPLASMIC ASTROCYTES |
| FIBROUS ASTROCYTES | with long delicate processes; abundant in white matter |
| PROTOPLASMIC ASTROCYTES | with many shorter processes; predominate in the gray matter |
| OLIGODENDROCYTES ETYMOLOGY | “OLIGOS”- Small/Few “DENDRON”- Tree “KYTOS”- Cell |
| OLIGODENDROCYTES | Extend many processes, each of which becomes sheet-like and wraps repeatedly around a portion of nearby CNS axon |
| OLIGODENDROCYTES | Smaller and nucleus is round, small, and dense Precursor of the myelin sheaths which facilitates rapid transmission of nerve impulses |
| OLIGODENDROCYTES | Processes are less numerous and shorter |
| OLIGODENDROCYTES Found in: | both white and gray matter of the CNS |
| OLIGODENDROCYTES | Most predominant glial cells in white matter |
| OLIGODENDROCYTES FUNCTIONS | MYELINATES and insulates CNS axons Allows faster action potential propagation |
| MICROGLIAL CELLS | Constitute the: major mechanism of immune defense in the CNS |
| MICROGLIAL CELLS | Removes any microbial invaders and secretes a number of immunoregulatory cytokines |
Created by:
1569455770155198