Terms For Lecture 14 Human Biology

Front 1

A neurotransmitter with many functions, including transmission of nerve signals to muscles at the neuromuscular junction. It is also the neurotransmitter for most of the autonomic nervous system, as well as for some synapses in the brain.

Back 1

acetylcholine

Front 2

An enzyme in nerve cells that breaks down acetylcholine.

Back 2

acetylcholinesterase

Front 3

Wave of depolarization and repolarization in a neuron propagated to the end of the axon. The amplitude of the depolarization is constant and does not diminish as the impulse moves away from the point where it initiated. Also called a nerve impulse.

Back 3

action potential

Front 4

Progressive mental deterioration in which there is memory loss along with the loss of control of body functions, ultimately resulting in death.

Back 4

Alzheimer's disease

Front 5

Almond-shaped structure in the brain’s temporal lobe that helps regulate emotional behaviors such as lust or rage. Also involved in relating memories to emotions.

Back 5

amygdala

Front 6

The branch of the nervous system that regulates involuntary actions. Subdivided into the sympathetic and parasympathetic nervous systems.

Back 6

autonomic nervous system

Front 7

Long, wire-like portion of the neuron that ends in a terminal bouton.

Back 7

axon

Front 8

Region of the brain that lies between the thalamus and the spinal cord that governs reflexes and some involuntary functions such as breathing and swallowing.

Back 8

brain stem

Front 9

Structure within each cerebral hemisphere that functions as part of the pathway that coordinates movement patterns, learning, and memory. Highly innervated by dopamine-releasing neurons originating in the midbrain.

Back 9

caudate nuclei

Front 10

Portion of the neuron that houses the nucleus and organelles. Also known as the soma.

Back 10

cell body

Front 11

The brain and the spinal cord. This part of the nervous system is responsible for integrating, processing, and coordinating information taken in by the senses and relaying instructions to muscles, glands and organs.

Back 11

central nervous system (CNS)

Front 12

Region of the brain that controls balance, muscle movement, and coordination.

Back 12

cerebellum

Front 13

Deeply wrinkled outer surface of the cerebrum where conscious activity and higher thought originate. It is the seat of functions such as intelligence, learning, memory, and emotion.

Back 13

cerebral cortex

Front 14

Protective liquid bath that surrounds the brain and spinal cord. The fluid is formed in the ventricles of the brain.

Back 14

cerebrospinal fluid

Front 15

Portion of the brain in which language, memory, sensations, and decision making are controlled. It has two hemispheres, each of which has four lobes.

Back 15

cerebrum

Front 16

Bundle of nerve fibers at the base of the cerebral fissure that provides a communication link between the cerebral hemispheres.

Back 16

corpus callosum

Front 17

Any of the 12 pairs of nerves in humans that arise from the midbrain or brain stem and connect to muscles and organs of the head, upper chest, and the thoracic and abdominal organs.

Back 17

cranial nerve

Front 18

Short extensions of the neuron that receive signals from other cells.

Back 18

dendrite

Front 19

Reduction in the charge difference across the neuronal membrane. Movement from a negative resting membrane potential toward a neutral (0 mV) or positive membrane potential.

Back 19

depolarization

Front 20

Disease that involves feelings of helplessness and despair, and sometimes thoughts of suicide.

Back 20

depression

Front 21

Central nervous system neurotransmitter in pathways that control emotions and complex movements.

Back 21

dopamine

Front 22

Muscle, gland, or organ stimulated by a nerve.

Back 22

effector

Front 23

A deep groove in the brain, such as the one that divides the cerebrum from front to back, into the right and left cerebral hemispheres.

Back 23

fissure

Front 24

The largest and most anterior lobe of each cerebral hemisphere.

Back 24

frontal lobe

Front 25

Groups of nerve cell bodies located outside the CNS.

Back 25

ganglion (pl: ganglia)

Front 26

Unmyelinated axons, combined with dendrites and cell bodies of other neurons that appear gray in cross section.

Back 26

gray matter

Front 27

Part of the limbic system of the brain that consists mainly of gray matter and plays a role in memory. , Located in the temporal lobe.

Back 27

hippocampus

Front 28

Part of the diencephalon of the brain whose function is to link the nervous system and the endocrine system. Helps regulate body temperature; influences behaviors such as hunger, thirst, and reproduction; and secretes several hormones that influence the master endocrine gland, the anterior pituitary. Also produces two hormones which are then secreted by the posterior pituitary.

Back 28

hypothalamus

Front 29

Combining multiple neural signals into one response.

Back 29

integration

Front 30

Neuron located between a sensory and a motor neuron that functions to integrate sensory input and motor output. The vast majority of the neurons are this functional type.

Back 30

interneuron

Front 31

A ring of interconnected brain structures involved in emotion, motivation, and behavior. Also called the “emotional-visceral” brain.

Back 31

limbic system

Front 32

The lower half of the brain stem. Conveys information between the spinal cord and other parts of the brain. Contains the cardiac, respiratory, vomiting and blood pressure control centers and regulates autonomic functions, such as breathing, heart rate and blood pressure.

Back 32

medulla oblongata

Front 33

Information stored in the brain for later retrieval.

Back 33

memory

Front 34

Membranes that surround the brain and spinal cord.

Back 34

meninges

Front 35

Uppermost region of the brain stem, which adjusts the sensitivity of the eyes to light and the ears to sound. Also has tracts connecting the lower brain stem to the diencephalon (including the thalamus and hypothalamus) and the cerebrum.

Back 35

midbrain

Front 36

A nerve that is composed of both sensory and motor fibers (axons). Most nerves are of this type.

Back 36

mixed nerve

Front 37

A neuron that carries information away from the brain or spinal cord to muscles or glands.

Back 37

motor neuron

Front 38

Protective layer that coats many axons, formed by supporting cells such as Schwann cells in the PNS nerves and oligodendrocytes in the CNS tracts. Greatly increases the speed at which the electrochemical impulse travels down the axon.

Back 38

myelin sheath

Front 39

A bundle of nerve fibers (axons) outside of the central nervous system, i.e. in the peripheral nervous system. These branch out from the brain and spinal cord, communicating with eyes, ears, internal organs, skin, and bones via electrochemical signals.

Back 39

nerve

Front 40

Electrochemical signal that controls the activities of muscles, glands, organs, and organ systems.

Back 40

nerve impulse

Front 41

A bundle of myelinated nerve fibers (axons) in the central nervous system. Outside of the central nervous system these are called nerves.

Back 41

nerve tract

Front 42

Brain, spinal cord, sense organs, and nerves that connect organs and link this system with other organ systems.

Back 42

nervous system

Front 43

The supporting cells of the nervous system. Although they do not propagate or transmit nerve impulses, members of this group of cell types are important in nourishing the nerves, providing myelin, protecting the nervous system against foreign invaders, creating cerebrospinal fluid, and creating scar tissue when parts of the CNS are damaged. Some types of these cells are found in the CNS and others in the PNS.

Back 43

neuroglia or glial cells

Front 44

Specialized message-carrying cell of the nervous system. Has the ability to propagate and transmit electrochemical signals that impart information.

Back 44

neuron

Front 45

One of many chemicals released by the presynaptic neuron into the synapse, which then diffuse across the synapse and bind to receptors on the membrane of the postsynaptic neuron.

Back 45

neurotransmitter

Front 46

Small indentation separating segments of the myelin sheath in the PNS. Nerve impulses "jump" successively from one indentation to the next, which allows nerve impulse transmission to be much faster in myelinated nerves than in unmyelinated nerves.

Back 46

node of Ranvier

Front 47

The posterior lobe of each cerebral hemisphere, containing the visual center of the brain.

Back 47

occipital lobe

Front 48

The division of the nervous system that stimulates digestive secretions, slows the heart, and constricts blood vessels. Its effects are opposite those of the sympathetic division of the nervous system.

Back 48

parasympathetic division

Front 49

Part of the brain that processes information about touch and is involved in self-awareness.

Back 49

parietal lobe

Front 50

Disease that results in tremors, rigidity, and slowed movements. May be due to faulty dopamine production in the midbrain.

Back 50

Parkinson's disease

Front 51

Network of nerves outside the brain and spinal cord that links the CNS with sense organs and effectors.

Back 51

peripheral nervous system (PNS)

Front 52

The second of three parts of the brainstem. A band of nerve fibers on the brain stem that links the medulla oblongata and the cerebellum with upper portions of the brain.

Back 52

pons

Front 53

The neuron that responds to neurotransmitter released from the presynaptic neuron.

Back 53

postsynaptic neuron

Front 54

The neuron that secretes neurotransmitter into a synapse, transmitting a signal.

Back 54

presynaptic neuron

Front 55

Involuntary, automatic response to a stimulus. The effector involved may be somatic (i.e. skeletal muscle) or autonomic (e.g. smooth muscle or a gland).

Back 55

reflex

Front 56

Nerve pathway in which sensory neurons signal motor neurons via the spinal cord, allowing a quick reflex response before the brain can respond. Has protective functions in that the individual can act before thinking, for instance to pull a hand back from a hot stove or shift the weight off a foot which has stepped onto a sharp object.

Back 56

reflex arc

Front 57

The period of rest after a neuron or muscle cell fires, before it can fire again.

Back 57

refractory period

Front 58

The restoration of a charge difference across a membrane. A return to resting membrane potential.

Back 58

repolarization

Front 59

The charge difference between the two sides of a membrane that occurs when a nerve cell is not conducting an impulse. All cells have a charge difference across their membranes but it is especially large in nerve cells, a fact which allows nerve cells to propagate and transmit nerve impulses.

Back 59

resting potential

Front 60

Extensive network of neurons that runs through parts of the brain stem and regulates consciousness and wakefulness. The part of the brain that wakes you up.

Back 60

reticular formation

Front 61

In neurons, the process by which neurotransmitters are reabsorbed by the neuron that secreted them.

Back 61

reuptake

Front 62

Glial cells that form the myelin sheath along the axons of nerve cells in the peripheral nervous system.

Back 62

Schwann cell

Front 63

A neuron that conducts impulses from a sense organ to the central nervous system.

Back 63

sensory neuron

Front 64

Cellular systems that collect information about the environment inside or outside the body and transmit that information to the brain. Often involve multiple tissue types in addition to the dendrites of a sensory nerve (such as epithelial and connective tissue), and may be organized into a discrete organ, such as the eyes.

Back 64

sensory receptors

Front 65

This protein pump in a cell membrane moves sodium out of the cell and potassium into the cell, both against their concentration gradients.

Back 65

sodium-potassium pump

Front 66

The part of the peripheral nervous system associated with movements of the skeletal muscles, whether voluntary or involuntary (i.e. reflex).

Back 66

somatic nervous system

Front 67

Thick cord of nervous tissue that extends from the base of the brain through the spinal column.

Back 67

spinal cord

Front 68

Nerves that branch off from the spinal cord to the rest of the body.

Back 68

spinal nerves

Front 69

The division of the autonomic nervous system that becomes active during stress.

Back 69

sympathetic division

Front 70

Gap between neurons consisting of a terminal bouton of the presynaptic neuron, the space between the two adjacent neurons, and the membrane of the postsynaptic neuron.

Back 70

synapse

Front 71

Part of the cerebral hemisphere that processes auditory and visual information, memory, and emotion. Located in front of the occipital lobe.

Back 71

temporal lobe

Front 72

Knob-like structure at the end of an axon.

Back 72

terminal bouton (axon terminal, terminal knob)

Front 73

Main relay center for sensory impulses between the spinal cord and the cerebrum. With the exception of the olfactory sense (sense of smell), all sensory pathways have a synapse in this structure.

Back 73

thalamus

Front 74

(1) In cardiovascular anatomy, one of the lower chambers of the heart that pumps blood from the heart to the lungs or to the systemic circulation(2) In the brain, any of the fluid-filled connecting cavities that lie more or less in the center of the brain.

Back 74

ventricle

Front 75

Nervous system tissue, especially in the brain and spinal cord, made of myelinated cells.

Back 75

white matter