lab exam 3 a&p1

Neuron

Specialized cell that transmits nerve impulses + Example: A neuron sends signals from the brain to muscles.

Cell body / Soma

Main part of the neuron that contains the nucleus and cytoplasm + Example: The soma controls the neuron’s activity.

Nucleus

Control center of the neuron + Example: The nucleus is found inside the soma.

Perikaryon

Cytoplasm inside the neuron cell body + Example: The perikaryon surrounds the nucleus in the soma.

Dendrites

Short branches that carry graded potentials toward the soma + Example: Dendrites receive input from other neurons.

Axon

Long part of a neuron that carries impulses away from the soma + Example: A motor neuron’s axon sends a signal to a muscle.

Axon hillock

Junction between the soma and axon + Example: The axon hillock is where the axon begins.

Myelin sheath

Covering around the axon that supports it and speeds up nerve impulses + Example: Myelin helps signals travel faster down the axon.

Oligodendrocytes

Cells that make myelin in the CNS + Example: Oligodendrocytes myelinate axons in the brain and spinal cord.

Schwann cells

Cells that make myelin in the PNS + Example: Schwann cells myelinate nerves outside the CNS.

Nodes of Ranvier

Gaps in the myelin sheath that help impulses move faster + Example: Action potentials jump from node to node.

Saltatory conduction

Movement of action potentials from one node of Ranvier to the next + Example: Saltatory conduction makes nerve impulses faster.

Synaptic knob / Synaptic bulb

End of the axon where neurotransmitters are released + Example: The synaptic knob releases acetylcholine.

Sensory neuron

Afferent neuron that carries impulses toward the CNS + Example: Sensory neurons carry pain signals to the spinal cord.

Afferent neuron

Neuron that carries signals toward the CNS + Example: A sensory neuron is afferent.

Interneuron

Neuron found completely inside the CNS that processes information + Example: An interneuron helps decide how the body responds to a stimulus.

Motor neuron

Efferent neuron that carries impulses away from the CNS + Example: A motor neuron tells a muscle to contract.

Efferent neuron

Neuron that carries signals away from the CNS + Example: Motor neurons are efferent.

Gray matter

Area made mostly of neuron cell bodies + Example: The spinal cord’s gray matter contains cell bodies

White matter

Area made mostly of axons + Example: White matter carries signals up and down the spinal cord.

Posterior horn

Gray matter area where sensory information enters + Example: Dorsal roots enter the posterior horn.

Anterior horn

Gray matter area where motor information leaves + Example: Ventral roots leave from the anterior horn.

Dorsal root

Root that carries sensory information into the spinal cord + Example: Pain signals enter through the dorsal root.

Ventral root

Root that carries motor information out of the spinal cord + Example: Muscle movement signals leave through the ventral root.

Central canal

Small opening in the center of the spinal cord + Example: The central canal is seen in spinal cord cross-section slides.

Satellite cells

Cells that surround sensory neurons in ganglia + Example: Satellite cells can be seen around sensory neurons on spinal ganglion slides.

Pyramidal cells

Pyramid-shaped excitatory neurons found in the cerebral cortex + Example: Pyramidal cells have long branching dendrites.

Purkinje cells

Neurons in the cerebellum that hep control motor coordination + Example: Purkinje cells help turn sensory input into motor output.

Stellate cells

Neurons found in the cerebrum and cerebellum that link other neurons + Example: Stellate cells connect with pyramidal and Purkinje cells.

Basket cells

Inhibitory interneurons in the cerebellum with short thick dendrites and a long axon + Example: Basket cells help regulate neuronal control.

Skeletal muscle

Voluntary muscle tissue that is striated and attached to bones + Example: Biceps muscle is skeletal muscle.

Smooth muscle

Involuntary muscle tissue with no striations and one central nucleus + Example: Smooth muscle is found in organs.

Cardiac muscle

Involuntary heart muscle that is striated and has intercalated discs + Example: The heart is made of cardiac muscle.

Striations

Stripe-like markings seen in skeletal and cardiac muscle + Example: Skeletal muscle has clear striations.

Intercalated discs

Special connections found only in cardiac muscle + Example: Cardiac muscle slides show intercalated discs.

Neuromuscular junction

Area where a motor neuron communicates with a muscle fiber + Example: ACh is released at the neuromuscular junction.

Acetylcholine / ACh

Neurotransmitter that helps start muscle contraction + Example: ACh binds to receptors on the motor end plate.

Synaptic cleft

Space between the neuron and muscle fiber + Example: ACh is released into the synaptic cleft.

Motor end plate

Area of the muscle fiber where ACh binds + Example: ACh receptors are found on the motor end plate.

Sarcolemma

Muscle cell membrane + Example: The action potential travels along the sarcolemma.

T-tubules

Tubes that carry the action potential into the muscle fiber + Example: T-tubules help the signal reach the sarcoplasmic reticulum.

Sarcoplasmic reticulum

Structure in muscle fibers that stores and releases calcium + Example: Calcium is released from the sarcoplasmic reticulum during contraction.

Troponin

Protein that calcium binds to during muscle contraction + Example: Calcium binding to troponin starts the crossbridge cycle.

Crossbridge cycle

Process that allows muscle fibers to contract + Example: The crossbridge cycle happens after calcium binds to troponin.

Steps of muscle contraction

Nerve signal reaches synaptic knob, calcium enters, ACh is released, ACh binds motor end plate, action potential travels through sarcolemma and T-tubules, calcium is released, calcium binds troponin, crossbridge cycle happens + Example: This process causes skeletal muscle contraction.

Spinal cord

Downward extension of the medulla oblongata + Example: The spinal cord carries signals between the brain and body.

Conus medullaris

Tapered end of the spinal cord near the first lumbar vertebra + Example: The spinal cord ends as the conus medullaris.

Spinal nerves

Nerves that emerge from the spinal cord in pairs + Example: Humans have 31 pairs of spinal nerves.

How many spinal nerve pairs are there?

31 pairs + Example: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

Cervical nerves

8 pairs of spinal nerves in the neck region + Example: C1 to C4 form the cervical plexus.

Thoracic nerves

12 pairs of spinal nerves in the chest region + Example: T3 to T5 help with respiration.

Lumbar nerves

5 pairs of spinal nerves in the lower back region + Example: L1 to L4 form the lumbar plexus.

Sacral nerves

5 pairs of spinal nerves in the sacral region + Example: Sacral nerves help form the sacral plexus

Coccygeal nerve

One spinal nerve pair that gives sensation to skin over the tailbone + Example: The coccygeal nerve supplies the tailbone area.

Cervical plexus

Nerve plexus formed by C1 to C4 + Example: It controls parts of the head, neck, and trunk.

Brachial plexus

Nerve plexus formed by C5 to C8 and T1 + Example: It controls the shoulder, arm, and hand.

Thoracic / Intercostal nerves

Nerves that affect the chest, back, abdomen, and respiration + Example: T6 to T12 help with back and abdominal muscles.

Lumbar plexus

Nerve plexus formed by L1 to L4 + Example: The femoral nerve comes from the lumbar plexus.

Femoral nerve

Largest nerve of the lumbar plexus that controls lower limb movement and sensation + Example: It affects the hips, legs, ankles, and feet.

Sacral plexus

Nerve plexus formed by L4, L5, and S1 to S3 + Example: The sciatic nerve comes from the sacral plexus.

Sciatic nerve

Largest nerve of the sacral plexus that supplies the foot, lower leg, and back of thigh + Example: Sciatic nerve pain can travel down the back of the leg.

Somatic reflex arc

Reflex arc involving skeletal muscle response + Example: The patellar reflex is a somatic reflex.

Visceral reflex arc

Reflex arc involving smooth muscle, cardiac muscle, or glands + Example: A reflex that changes heart rate is visceral.

Biceps reflex

Reflex that causes flexion of the arm and uses C5 and C6 nerves + Example: Tapping the biceps tendon should bend the arm.

Triceps reflex

Reflex that causes extension of the arm and uses C7 and C8 nerves + Example: Tapping the triceps tendon should extend the arm.

Patellar reflex

Knee jerk reflex that uses L2, L3, and L4 nerves + Example: Tapping below the kneecap makes the lower leg kick upward.

Hyporeflexia

Diminished reflex response to a stimulus + Example: Aging or neuronal lesions can cause hyporeflexia.

Hyperreflexia

Exaggerated reflex response due to loss of inhibitory control from the motor cortex + Example: A very strong knee jerk can show hyperreflexia.

Meninges

Three membranes surrounding the brain + Example: Dura mater, arachnoid mater, and pia mater are meninges.

Dura mater

Outermost thick and tough meninx made of fibrous connective tissue + Example: The dura mater protects the brain.

Arachnoid mater

Middle netlike meninx below the dura mater + Example: The subarachnoid space is near the arachnoid mater.

Subarachnoid space

Space that contains cerebrospinal fluid + Example: CSF is found in the subarachnoid space.

Pia mater

Thin meninx directly on the surface of the brain + Example: Pia mater follows the grooves of the brain.

Cerebral hemispheres

Two halves of the cerebrum + Example: The brain has left and right cerebral hemispheres.

Longitudinal cerebral fissure

Groove that separates the left and right cerebral hemispheres + Example: The longitudinal fissure divides the cerebrum in half.

Cerebral cortex

Folded outer surface of the cerebrum + Example: The cerebral cortex contains gyri and sulci.

Gyri

Ridges on the brain surface + Example: The precentral gyrus is a ridge.

Sulci

Grooves on the brain surface + Example: The central sulcus separates the frontal and parietal lobes.

Contralateral control

Each brain hemisphere controls the opposite side of the body + Example: The left hemisphere controls the right side.

Corpus callosum

Thick bundle of nerve fibers connecting the left and right hemispheres + Example: The corpus callosum allows the hemispheres to communicate.

Central sulcus

Groove that separates the frontal lobe from the parietal lobe + Example: The precentral gyrus is in front of the central sulcus.

Frontal lobe

Brain lobe involved in problem solving, decision making, motor planning, and cognition + Example: Broca’s area is in the frontal lobe.

Parietal lobe

Brain lobe involved in sensory perception + Example: The postcentral gyrus is in the parietal lobe.

Precentral gyrus

Primary motor cortex in front of the central sulcus + Example: It controls voluntary movement.

Postcentral gyrus

Somatosensory cortex behind the central sulcus + Example: It processes touch.

Sylvian fissure

Fissure that divides the temporal lobe from the cerebral hemisphere + Example: The temporal lobe lies below the Sylvian fissure.

Temporal lobe

Brain lobe involved in auditory signals, learning, and memory + Example: Wernicke’s area is in the temporal lobe.

Insula

Brain area involved in taste and smell + Example: The insula contains gustatory and olfactory cortex areas.

Wernicke’s area

Area responsible for understanding spoken language + Example: Damage to Wernicke’s area can affect language comprehension.

Broca’s area

Area responsible for speech production + Example: Broca’s area coordinates muscles of the tongue and mouth.

Occipital lobe

Back part of the brain that processes visual information + Example: The occipital lobe helps with spatial reasoning.

Cerebrum

Largest and most anterior part of the brain responsible for higher functions + Example: The cerebrum handles reasoning and emotions.

Medulla oblongata

Area where the brain and spinal cord connect and controls vital functions + Example: The medulla controls breathing and heart rate.

Cerebellum

Little brain that controls muscle control, balance, and movement + Example: The cerebellum helps you walk steadily.

Arbor vitae

Tree-like white matter inside the cerebellum + Example: Arbor vitae can be seen in internal brain anatomy.

Thalamus

Brain area that relays sensory information to the cerebral cortex except smell + Example: The thalamus helps with sleep and consciousness.

Hypothalamus

Brain area that produces hormones and maintains homeostasis + Example: The hypothalamus controls hunger and body temperature.