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This unit covers chapters: 7,11,43,44,45

This unit covers chapters: 7,11,43,44,45. Evolution. Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes The concentration of signaling molecules allows bacteria to sense local population density.

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This unit covers chapters: 7,11,43,44,45

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  1. This unit covers chapters: 7,11,43,44,45

  2. Evolution • Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes • The concentration of signaling molecules allows bacteria to sense local population density

  3. Cell Membrane structures that aid in communication Ch. 7 • Animal and plant cells have cell junctionsthat directly connect the cytoplasm of adjacent cells • Tight Junctions • Desmosomes • Gap Junctions

  4. Tight Junctions-prevent leakage of extra cellular fluid by making a tight seal around adjacent cells. Ex: skin cells • Desmosomes-acts like a rivet, attaching cells together. Ex: muscle cells, if a muscle tears then a desmosome has ruptured. • Gap Junctions- in animals and Plasmodesmata in plants allows ions, amino acids, and sugars to transport between cells

  5. Membrane Protein functions • Transport • Signal Transduction • Cell to Cell recognition • Intercellular joining • Attachment to cytoskeleton

  6. Feedback • Positive Feedback Negative Feedback Which is an example is each: • Temperature regulation _______________ • Lactation in mammals _________________ • Blood Clotting ______________________ • Secretion of Insulin __________________

  7. SOOOO…… • How would you describe Positive Feedback? • How would you describe Negative Feedback?

  8. Chapter 11 Cell Communication

  9. Signal-Transduction Pathway • Signal on a cell’s surface is converted into a specific cellular response • Local signaling(short distance) - Paracrine (growth factors); Synaptic (neurotransmitters) • Long distance- hormones

  10. Stages of Cell Signaling 3 steps: • Reception: target cell detection • Transduction: single-step or series of changes • Response: triggering of a specific cellular response

  11. Immunity and Cell Communication Ch 43

  12. Types of immune responses • Humoral immunity • B cell activation • Production of antibodies • Defend against bacteria, toxins, and viruses free in the lymph and blood plasma

  13. Cell-mediated immunity • T cell activation • Binds to and/or lyses cells • Defend against cells infected with bacteria, viruses, fungi, protozoa, and parasites; nonself interaction

  14. Immunity in Health & Disease • Active immunity/natural: conferred immunity by recovering from disease • Active immunity/artificial: immunization and vaccination; produces a primary response • Passive immunity: transfer of immunity from one individual to another • natural: mother to fetus; breast milk • artificial: rabies antibodies

  15. The Inflammatory Response 1- Tissue injury; release of chemical signals~ • histamine (basophils/mast cells): causes Step 2... • prostaglandins: increases blood flow & vessel permeability 2/3- Dilation and increased permeability of capillary 4- Phagocytosis of pathogens~ • fever- leukocyte-released molecules increase body temperature

  16. Nervous System and cell communication Ch 48

  17. Parts of Neuron-Nervous System Cell • Neuron~ structural and functional unit • Cell body~ nucelus and organelles • Dendrites~ impulses from tips to neuron • Axons~ impulses toward tips • Myelin sheath~ supporting, insulating layer • Schwann cells~PNS support cells • Synaptic terminals~ neurotransmitter releaser • Synapse~ neuron junction • Neurotransmitters- chemical messengers that pass information from transmitting to receiving neurons

  18. Sensory Receptors~ dendrites receive stimulus and send to CNS which will relay to Effector cells • Effector cells~ muscle or gland cells that will produce a desired response • Nerves~ bundles of neurons wrapped in connective tissue • Central nervous system (CNS)~ brain and spinal cord • Peripheral nervous system (PNS)~ sensory and motor neurons

  19. Sensory neuron: convey information to spinal cord • Motor neurons: convey signals to effector cell (muscle or gland) • Reflex: simple response; sensory to motor neurons.

  20. Is typically -60 to -80 millivolts

  21. Endocrine and cell communication Ch 45

  22. Regulatory systems • Hormone~ chemical signal secreted into body fluids (blood) communicating regulatory messages • Target cells~ body cells that respond to hormones • Endocrine system/glands~ hormone secreting system/glands (ductless); • Exocrine glands~ secrete chemicals (sweat, mucus, enzymes) through ducts • Neurosecretory cells~ actual cells that secrete hormones • Feedback mechanisms ~ negative and positive

  23. Mode of Action: Chemical Signaling 1- Plasma membrane reception • signal-transduction pathways (neurotransmitters, growth factors, most hormones) 2- Cell nucleus reception • steroid hormones, thyroid hormones, some local regulators

  24. Hypothalamus~regulates the pituitary glandPituitary glandPineal glandThyroid glandParathyroid glandsThymusAdrenal glandsPancreasGonads -ovary, testis

  25. Pineal-secretes serotonin which regulates the sleep/wake cycles • Thyroid- regulates metabolism • Parathyroid- control calcium level in bones and blood • Thymus-secretes hormones that produce antibodies • Adrenal- secretes aldosterone and cortisol which creates a fight or flight response • Gonads-secrete testosterone, esterogen, or progesterone • Pancreas- secretes Insulin and Glucagon to regulate blood sugar levels

  26. Examples of Hormone Regulation • Pituitary: Regulates other glands • Oxytocin: uterine and mammary gland cell contraction • Antidiuretic (ADH):retention of water by kidneys

  27. Pituitary Gland regulates • Growth (GH)~bones • Disorder: gigantism/dwarfism • Prolactin (PRL)~mammary glands; milk production • Follicle-stimulating (FSH) – this causes the sex cells to finish meiosis and prepare for sexual reproduction • Luteinizing (LH)~ovaries/testes- helps maintain levels of sex hormones in the body

  28. Thyroid-stimulating (TSH)~ regulates metabolism • Adrenocorticotropic (ACTH)~ aids in body’s response to stress • Melanocyte-stimulating (MSH) has effects on skin pigmentation • Endorphins~natural ‘opiates’; brain pain receptors

  29. MSH • Interesting fact about MSH : However, in many red headed people, and other people who do not tan well, there are variations in their hormone receptors, causing them to not respond to MSH in the blood.

  30. The pancreas (organ) Hormones secretes by the pancreas to regulate Blood Sugar • glucagon~ raises blood glucose levels • insulin~ lowers blood glucose levels

  31. Ch 44 Excretory • With focus on the Kidneys, Ureter, Bladder, and Urethrea • Other organs involved in excretory would be skin and lungs

  32. The Kidneys (organ)

  33. Role of ADH • When the brain detects dehydration it will secrete ADH. • ADH will reduce amt of water in urine. • Secretion stops when the blood volume returns to homeostasis.

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