phys notes pt 1. (cells/nervous system)

wafl 1

proliferation

rapid tissue growth through cell division

differentiation

cells specialize and get an idenity

cell types

muscle cells

neurons

epithelial cells

connective tissue cells

extracellular matrix

composed of non living molecules outside of the cell

provides physiochemical environment

structural support

allows nutrients and chem to pass freely

soluble polymers

binds to water

made of glycosaminoglycans, proteoglycans, and other macromolecules.

insoluble protein fibers

provide structural support and strength in tissues, contributing to the extracellular matrix.

made of collagen and elastin

hyperplasia

tissue growth due to increase in number of cells

occurs through proliferation

hypertrophy

tissue grows from increased size of cells

homeostasis

stable condition of internal environment

• dynamic constancy

  • negative & positive feedback

feed forward regulation

anticipatory change in variable, body makes changes prior to an event occuring

reflex arc

receptor —> afferent pathway

—> integrating center (brain) —> efferent pathway

—> effector

receptors

protein structure that interacts with a chemical messenger

affinity

strength of binding and determines strength of cellular response

peripheral nervous system

contains the afferent and efferent pathways and the communication of nerves

afferent nerves

sends sensory information to the CNS

efferent nerves

receives info from the CNS and sends it to the rest of the body; contains automatic and somatic system

autonomic nervous system

visceral efferent neurons; involuntary movement

sympathetic and parasympathetic systems;

results in either excitation or inhibition

preganglionic and post ganglionic neuron

somatic nervous system

voluntary movement; only results in excitation from an alpha neuron

cholinergic (only secretes acetylcholine)

chemical messengers

ligands; neurotransmitters & hormones

mechanisms: paracrine & autocrine

non chemical messengers

gap junctions (membrane channel between cells)

juxtracrine (no secretion, messenger attached to cell)

diffusion

movement down concentration gradient

no energy needed

simple diffusion

direct passage of uncharged molecules down a concentration gradient

facilitated diffusion

uses proteins to help move charged molecules

active transport

movement against concentration gradient

ex. sodium & potassium pump

endocytosis

cell engulfs/eats molecule to bring it in the cell

exocytosis

cell expels molecule from within the cell membrane —> extracellular space

mitosis

cell division when DNA is duplicated and same amount of chromosomes are passed down

meiosis

cell division that creates a gamete and receives half the chromosomes

epithelial cells

lines surface of organs

selective permeability

protection

continuously proliferative

connective tissue cells

exchange of nutrients, gases, and waste between cells

structural support and protection

muscle cells

specialized in contractions

movement

actin / myosin

neurons

specialized in initiation and conduction of action potentials

plasticity

exocrine glands

secretes onto external surfaces through ducts

ex. GI tract

endocrine glands

ductless glands that secrete messengers into blood

paracrine glands

secrete substances into interstitial fluids and nearby target cells

sympathetic nervous system

thoracolumbar division; localized OR widespread effects on body

secretion of catecholamines (epi/norepi)

fight or flight

postganglionic neurons are noradrenergic

parasympathetic nervous system

craniosacral division; only localized effects on body

rest & digest

only cholinergic (acetylcholine)

includes vagus nerve

preganglionic neuron

cell body in CNS

myelinated and cholinergic

ACh binds to NAChR on postganglionic neuron

postganglionic neuron

cell body is in PNS

unmyelinated

can be cholinergic or noradrenergic

innervates peripheral visceral tissue

has varicosities on the ends

ACh binds to MAChR

norepinephrine binds to alpha/beta receptors

fight or flight

primitive response of SNS that promotes survival

widespread SNS activation —> visceral response

triggers: fear, stress, exercise

response:

increased HR, BP, respiratory rate, dilation of bronchi, glucose levels

goose bumps

decreased clotting

autonomic dysflexia

spinal cord injury at or above T6

common triggers: urological distension, bowel distension, skin problems

symptoms:

increased BP

decreased HR

flushed face / sweaty

blurred vision & headache

goose bumps / anxiety

vasovagal syncope

vasodepressor; reflex syncope; bid daddy nerve meltdown

abnormal pattern of autonomic activation to maintain BP

symptoms: fainting, decreased HR & BP, blurry vision, nausea

triggers: blood, heat, fear, pain, emotional stress

autonomic dysfunction

autonomic failure; usually combined with other neurological disorders

ex. parkinsons

autonomic neuropathy

nerve damage to autonomic neurons

common cause is diabetes mellitus

symptoms:

dizziness/fainting

intolerance to exercise

abnormal sweating

sexual dysfunction

urinary/digestive issues