cbio 2200 final (robinson)

Organization of the nervous system.

two major subdivisions are the central nervous system and the peripheral nervous system

Central nervous system

brain and spinal cord

peripheral nervous system.

spinal and cranial nerves and ganglia

Peripheral divisions.

sensory (somatic sensory division, visceral sensory division) and motor (visceral motor division -> sympathetic & parasympathetic divisions, somatic motor division)

Somatic sensory division.

carriers signals from receptors in skin, muscles, bones, and joints

Visceral sensory division.

carries signals from the viscera (lungs, heart, stomach, and urinary bladder)

Somatic motor division.

carriers signals to skeletal muscles, out produces muscular contraction and somatic reflexes/involuntary muscle contractions

Visceral motor division

carries signals to glands, cardiac and smooth muscles

Sympathetic division.

arouses body for action, accelerates heartbeat and respiration, also inhibits digestive and urinary systems

Parasympathetic division.

has a calming effect, slows heart rate and breathing, also stimulates digestive and urinary systems

Structure of neurons

soma that has a centrally located nucleus; cytoplasm contains mitochondria, lysosomes, golgi complex, rough ER, and ;Cytoskeleton is made of a dense mesh of microtubules and neurofibrils

Types of neurons.

sensory (afferent), interneurons, and motor (efferent)

sensory neurons.

detect stimuli and transmit information about them toward the CNS

Interneurons.

connect motor and sensory pathways, and receive signals from many neurons and carry out integrative functions

Motor neurons.

send signals to muscles and gland cells (effectors)

Multipolar neuron.

one axon and multiple dendrites, most neurons in the CNS

Bipolar neuron.

one axon and one dendrite, olfactory cells, retina, inner ear

Unipolar neuron

single process leading away from soma, sensory cells from skin and organs to spinal cord

Anaxonic neuron.

many dendrites and no axon, retina, brain, and adrenal gland

Types of neuroglia

oligodendrocytes, ependymal cells, microglia, and astrocytes

Oligodendrocytes.

form myelin sheaths in the CNS that speed signal conduction, arm-like processes wrap around nerve fibers

Ependymal cells

line internal cavities of the brain, secrete and circulate cerebrospinal fluid (CSF)

Microglia.

develop from WBCs and become concentrated in areas of damage

Astrocytes

Most abundant neuroglia in CNS; Cover brain surface and most nonsynaptic regions of neurons; Diverse functions: create supportive framework, form the blood-brain barrier, monitor activity; regulate blood flow to match metabolic need, convert glucose to lactate, secrete nerve growth factors, communicate electrically with neurons, regulate chemical composition of tissue fluid

Neuroglia in the PNS.

schwann cells and satellite cells

Schwann cells.

wind around the axon, form myelin sheaths, assist in regeneration of damaged fibers

Satellite cells.

surround the somas of PNS neurons inside ganglia, provide electrical insulation, and regulate the chemical environment

Signal conduction in nerve fibers

Unmyelinated axons have voltage-gated channels along their entire length; AP at trigger zone causes Na+ to enter axon and diffuse into adjacent regions; Depolarization opens voltage gated channels; Opening of voltage gated channels results in a new AP which then allows Na+ diffusion to excite membrane immediately distal to that; Chain reaction continues down axon

Acetylcholine.

excites skeletal muscle, inhibits cardiac muscle, and has excitatory effects or inhibitory effects on smooth muscle and glands depending on locations

Glutamate.

accounts for 75% of all excitatory synaptic transmission in the brain, involved in learning and memory

Aspartate.

effects similar to those of glutamate

Glycine.

most common inhibitory neurotransmitter in the spinal cord

GABA.

most common inhibitory neurotransmitter in the brain

Norepinephrine.

involved in dreaming, waking, and mood; excites cardiac muscle, can excite or inhibit smooth muscle depending on location

Epinephrine.

effects similar to those of norepinephrine

Dopamine.

involved in elevation of mood and control of skeletal muscles

Serotonin.

involved in sleepiness, alertness, thermoregulation, and mood

Histamine.

vasodilator

Substance P.

mediates pain transmission

Enkephalins.

inhibit intestinal motility, modulate immune response

B-endorphin.

suppresses pain, secretion rises during labor and delivery

Cholecystokinin.

suppresses appetite

Cerebrum (including special functions of the gyrus)

seat of sensory perception, memory, thought, judgement, and voluntary motor actions; Gyri increase amount of cortex in the cranial cavity allowing for more information processing capability

Frontal lobe.

voluntary motor functions, motivation, foresight, planning, memory, mood, emotion, social judgement, and aggression

Parietal lobe.

integrates general senses, tastes, and some visual info

Occipital lobe.

primary visual center of brain

Temporal lobe.

functions in hearing, smell, learning, memory, and some aspects of vision and emotion

Insula.

helps in understanding spoken language, taste, and integrating info from visceral receptors

Cerebellum.

important for motor coordination and locomotor activity

Brainstem.

medulla oblongata, pons, and midbrain

Medulla oblongata.

controlling heart rate, blood pressure, and breathing (cardiovascular/respiratory centers), as well as managing reflex actions like vomiting, swallowing, coughing, and sneezing.

Pons.

regulates vital, unconscious functions including breathing, sleep cycles, and REM sleep, while relaying sensory and motor signals between the cortex and cerebellum

Midbrain.

eye movement, motor control, arousal, sleep/wake cycles, and temperature regulation.

Diencephalon.

includes the thalamus, hypothalamus, and epithalamus

Thalamus.

processes info on its way to the cerebral cortex, plays a key role in motor control, involved in memory and emotion

Hypothalamus.

major control center of autonomic nervous system and endocrine system, hormone secretion, autonomic effects, thermoregulation, food and water intake, sleep and circadian rhythms, memory, and emotional behavior and sexual response

Homeostasis.

a dynamic state of equilibrium; All body systems contribute to homeostasis but the nervous & endocrine are most important

Feedback mechanisms.

there are positive and negative feedback mechanisms

Negative feedback.

output shuts off the original effect of the stimulus or reduces its intensity, most feedback mechanisms of the body

Positive feedback.

output accelerates the original effect of the stimulus or increases its intensity, examples include labor contractions, platelet plug formation, & milk let down

Plasma membrane.

flexible outer boundary made of proteins and lipids (lipid bilayer)

Plasma membrane (lipid bilayer) functions.

defines cell boundaries, governs interactions with other cells, & controls passage of materials in and out of the cell; Also separates ECF and ICF

Types of membrane lipids.

phospholipids, cholesterol, & glycolipids

Phospholipids.

hydrophilic heads face water on each side of membrane & hydrophobic tails are directed toward the center avoiding water

Cholesterol.

holds phospholipids in place/still and can stiffen membrane; People in colder climates have more cholesterol in their bilayer

Glycolipids.

contributes to the carbohydrate coating on cell surface

Types of membrane proteins.

integral proteins, peripheral proteins, & second messenger system

Integral proteins.

penetrate membrane

Peripheral proteins.

adhere to one face of the membrane

Second messenger system-

1st messenger -> receptor -> G-protein -> enzyme -> 2nd messenger -> amplify

Plasma membranes are.

selectively permeable & use active + passive processes for substances to cross the membrane

Passive process.

no ATP required, substance moves down its concentration gradient, two types: diffusion & filtration

Diffusion.

moves from high to low concentration, includes simple diffusion, carrier and channel mediated facilitated diffusion, and osmosis

Filtration.

particles are driven through membrane by physical pressure

Non-polar lipid-soluble substances.

diffuse directly through phospholipid bilayer

Carrier mediated facilitated diffusion.

transmembrane integral proteins are carriers, binding of substrate causes shape change for the carrier then passage across the membrane

Osmosis.

occurs when water concentration differs on the two sides of the membrane, use water specific channels called aquaporins, movement of solvent across the selectively permeable membrane

Gradients.

a difference in a variable between one point and another ; Down the gradient means that substances are moved from areas of higher concentration to areas of lower concentration; Up the gradient means that substances are moved from areas of low concentration to areas of high concentration

Active process.

requires ATP to move solutes across membrane, two types include active transport and vesicular transport

Primary active transport.

carrier moves solute through membrane up its concentration gradient, example is the Na/K pump

Secondary active transport.

carrier moves solute through membrane but atp is only used indirectly

Vesicular transport.

transport of large molecules, macromolecules, and fluids across membrane in membranous sacs called vesicles, requires ATP ; Types include: endocytosis, exocytosis, transcytosis, and vascular trafficking

Endocytosis.

brings material into cell

Phagocytosis.

cell eating, engulfing large particles (immune system)

Pinocytosis.

cell drinking, taking in droplets of ECF

Receptor mediated endocytosis.

particles bind to specific receptors on plasma membrane

Transcytosis

transport of material across cell by capturing it on one side and releasing it on the other

Exocytosis.

secreting material

Types of tissues.

nervous, muscle, epithelial, & connective tissues

Nervous tissue.

internal communication; includes the brain, spinal cord, and nerves ; Transmit electrical signals from sensory receptors and to effectors which control their activity

Muscle tissue.

contracts to cause movement; includes muscles attached to bones (skeletal), muscles of heart (cardiac), and muscles of walls of hollow organs (smooth) ; Skeletal: voluntary movement, locomotion,manipulation of the environment, facial expression, voluntary control; Cardiac: as it contracts it propels blood into the circulation, involuntary control; Smooth: propels substances or objects along internal passageways, involuntary control

Epithelial tissue.

forms boundaries between different environments, protects, secretes, absorbs, filters; skin surface (epidermis), lining of GI tract organs and other hollow organs; Avascular & nourished by underlying connective tissue; Protect deeper tissue from injury & infection; Produce & release chemical secretions; Absorb chemicals including nutrients; Selectively filter substances; Sense stimuli; know types and locations

Connective tissue.

supports, protects, binds other tissues together; bones, tendons, fat and other soft padding tissue; Connective tissue proper: wraps & cushions organs, provides reserve food fuel, insulates against heat loss, attach muscles to bones or muscles; Cartilage: avascular, eases joint movement, holds airways open, provides flexible/elastic support, resists compression and absorbs shock; Bone tissue; Blood

Ectoderm.

gives rise to epidermis and nervous system

Endoderm.

gives rise to mucous membrane lining digestive and respiratory tracts

Mesoderm.

gives rise to cartilage, bone, blood

Tissue growth.

increasing the number of cells or size of existing cells

Hyperplasia.

growth through cell multiplication

Hypertrophy.

enlargement of preexisting cells

Neoplasia.

development of a tumor