Lecture 4- Exam 2

intercellular communication- indirect

involves extracellular signals (chemical messengers) because cells aren’t touching (text, call, write message)

signal is released outside the sending cell (extracellular) and chemical’s signals composition tells the receiving cell what to do (key), all signals are some sort of chemical

primary types of indirect communication

paracrine, neurotransmitter, endocrine (hormones)

where do paracrines come from?

almost all cells in the body

(green cells in middle are paracrines)

where do paracrines go to?

nearby cells (communication can be overheard by other people)

where do paracrines travel?

fluid between cells (interstitial fluid: watery liquid that fills the spaces around cells in the body) (water)

special case for paracrines

autocrines: cell sends message to itself (example: taking notes in class to organize thoughts and remember later)

where do neurotransmitters come from?

only neurons

where do neurotransmitters go to?

only adjoining cells (not attached, requires space/synapse connection)

example: whispering to a friend to avoid others from hearing

where do neurotransmitters travel?

fluid between cells

endocrine

hormones

where do endocrines come from?

only gland or neuron

nervous system often releases endocrines to initiate the endocrine system to get started

where do endocrines go to?

distant cells (move into our blood) (goes through cells)

blood delivers oxygen adn substances to all cells, enabling long distance communication

example: we can hear a voice from Cincinnati or Toledo

where do endocrines travel?

blood (plasma)

special case for endocrines

neurohormone: a special name for endocrines released from a neuron (source is not a gland, its a neuron) (historically known as neuroendocrine)

how can paracrines and neurotransmitters be grouped

location being sent to (both nearby cells)
where they travel (both fluid between cells)

paracrines and neurotransmitters are both being sent to? While endocrines are being sent to?

paracrines + neurotransmitters: nearby cells

endocrines: distant cells

paracrines and neurotransmitters both travel via? While endocrines travel via?

paracrines and neurotransmitters: fluid between cells (water)

endocrines: blood

smallest component of body

cells

mitosis

process for creating new cells from a single fertilized egg cell for growth and repair (not meiosis, which creates egg/sperm)

multicellular organism (metazoin)

genome

identical DNA

proteome

different proteins in different cell types (proteins made from DNA but specialized cells have different jobs because of different proteins)

example: heart cell proteins differ from neuron proteins

lipidome

different lipids (fats) in different cell types, lipids also perform specific jobs

example: heart cell fats differ from neuron fats

DNA is blueprint but still have different components

cells use different parts of the same DNA blueprint to perform specific functions (neurons, cardiac cell)

analogy: two people writing papers from the same library, but using different sources to create different papers

primary cell types

cells are surrounded by water/fluid except epithelial cells interact with air

epithelial cells

muscle cells

neurons

connective

epithelial cells

out/in boundary, interact with air on one side

examples: skin, lining of respiratory system (lungs), digestive system, renal system

figure 6

muscle cells

mechanical movement

examples: skeletal muscle (movement), cardiac muscle (heart squeeze), smooth muscle (stomach squeezing)

figure 7

neurons

electrical communication, generate and move electrical activity over long distances (up to a meter)

figure 8

connective cells

support one or more of the other three categories, support can be physical or metabolic

example: red blood cells do not generate electrical activity, mechanical movement, or form boundaries. They provide metabolic support by delivering oxygen to other cell types, which is essential for ATP production via equation 2

figure 9

tissues (putting cells together)

defined as groups of cells of the same primary type so 4 main types of tissues (epithelial, muscle, neurons, connective)

organs (group of cells)

combinations of tissues (vary in proportion and pattern), organs function is defined by its specific combination and arrangement of tissues

figure 10

functional unit of organs

smallest part of an organ that performs the overall job of the organ (cells and tissues don’t have functional units)

example: the nephron is the functional unit of the kidney. Understanding one nephron’s function helps understand the whole kidney’s function

figure 11

redundancy

if some functional units fail, the organ can still function (kidneys still work wiht less than 100 percent nephrons functioning)

example: someone sick in a business but the whole office doesn’t shut down and it can still work

redundancy exception

the heart is considered only one functional unit in humans, lacking redundancy. Loss of heart function leads to disaster without quick intervention

expansion

more functional units can be added to an organ without shutting down existing operations

example: training new workers for a business expansion

organ/body systems

a collection of organs with related functions, also called body systems, maintain one or more parameters in homeostasis (steady state at a set point)

examples of organ/body systems

renal system (kidneys, ureters, bladder) for urine production and excretion, circulatory system (heart, blood vessels), immune system

figure 10

organ systems can what?

overlap

example: the immune system heavily relies on the circulatory system to transport soldier cells (antibodies) throughout the body