Immunity and Internal Defense

Biology 200 - Exam 4

phagocytic cells (internal defense)

1. phagocytic cell brings the pathogen inside and it’s in a vacuole

2. vacuole fuses with lysosome and pathogen is destroyed

3. phagocyte cell spits out destroyed pathogen

toll-like receptors

phagocytic cells (WBC) have

phagocytic cells

recognize fragments of molecules found on a set of pathogens

• recognized molecules normally ABSENT from vertebrate body and an essential component of a class of pathogens

• ex: flaggelin (main protein of bacterial flagella)

two phagocytic cell types

• neutrophils

• macrophages

neutrophils

circulate in blood, attracted to infected tissue, destroy pathogens

macrophages

big eaters

some move around body

others live permanently in tissues

likely to encounter pathogens

natural killer cells

• circulate body

• detect abnormal array of surface proteins typically of virus-infected or cancerous cells

• release chemicals that lead to cell death

inflammatory response

• damage to body (splinters)

  -

• histamines released by mast cells = vasodilation of capillaries

  -

• vasodilation delivers phagocytes to area

  -

• pus: fluid filled with WBC’s and dead microbes

histamines

mast cells released by

pus

fluid filled with WBC’s and dead microbes

lymphatic system

• lymph vessels + structure that trap foreign substances

  -

• lymph = fluid that flows through lymphatic system

  -

• intersitial fluid + WBC’s continually enter lympth vessels

  -

• within lymph nodes, high concentrations of defense cells

lymph

fluid that flows through the lymphatic system

adaptive immunity

• found only in vertebrates

• develops more slowly than innate

• detects pathogens with specificity

B and T cells

• lymphocytes made in bone marrow

• T cells mature in Thymus; B cells in Bone marrow

• recognize antigen with antigen receptors

T cells

mature in thymus

B cells

mature in bone marrow

lymphocytes (B and T cells)

made in bone marrow

Antigens (protein or polysaccaharides)

• foreign substances that elicits a B or T cell response

• usually - or - that protrude from surface of foreign cells or viruses

major histocompatibility complex (MHC) molecules

proteins that display antigen fragments on cell surface

MHC I

on most body cells

MHC I

bind and display fragments of foreign antigens made WITHIN cells

MHC II

on antigen-presenting cells (eg. cells, macrophages)

MHC II

bind and display antigens internalized through phagocytosis

helper T cells

• activate humoral and cell-mediated immunity

• must themselves be activated by antigen-presenting cell that is displaying an antigen

role of antibodies

• neutralization

  • blocking of ability of a virus to bind to a host cell

• opsonization

  • promotion of phagocytosis of bacteria by macrophages and neutrophils

neutralization

blocking of ability of a virus to bind to a host cell

opsonization

promotion of phagocytosis of bacteria by macrophages and neutrophils

primary immune response

1st time B and T cells encounter antigen

secondary immune response

2nd time B and T cells encounter antigen

secondary response

• 2nd time B and T cells encounter antigen

• antibodies increase faster and with greater magnitude because of memory cells

passive immunity

short term immunity conferred by transfer of antibodies (maternal antibodies transferred to fetus or nursing infant, blood transfusions)

active immunity

• defenses that arise when a pathogen infects body and prompts a primary or secondary immune response

  -

• vaccination introduces antigens into body (dead microbes, parts of microbes) - induces a primary response

  -

• results from the production of antibodies by the immune system in response to the presence of an antigen

vaccination programs

• successful against many infectious diseases

• worldwide eradication of smallpox in the 1970’s

• studies do not make a link with autism

osmoregulation

process of how animals control solute concentration and balance water loss/gain

• relative concentrations of water and solutes must be kept in a narrow range (homeostasis)

osmolarity

total [solute] expressed as (moles of solute)/L

• mOsm/L = milliosmoles/L

• reference values → sea water (1000 mOsm/L) and blood (300 mOsm/L)

isoosmotic

same solute concentration on both sides

hyperosmotic

higher solute concentration

hypoosmotic

lower solute concentration

antibody

soluble form of the B-cell antigen receptor

osmoconformer

isoosmotic with surroundings (marine invertebrates)

• ex: jellyfish, sea slugs

osmoregulator

control its internal osmolarity independent of its environment

marine osmoregulator (hypoosmotic)

• lower [solute] than ocean

• animals constantly losing water

• balance water loss by drinking water and ridding excess salt through kidneys/gills

freshwater osmoregulator (hyperosmotic)

• higher [solute] than river

• constantly gaining water

• drinks little water, excretes LOTS of dilute urine

anhydrobiosis

dormant state involving loss of almost all body water

• tardigrades (invertebrate)

land animals

• body coverings help prevent dehydration

• desert organisms are nocturnal

• drink water, eat moist foods, generate water through respiration

nitrogenous waste

• breakdown product of protein and nucleic acid

• enzymes remove nitrogen in form of ammonia (NH₃)

Ammonia (NH₃)

• tolerated at low concentrations (in the bloodstream)

• need access to lots of water

• fish - _________ lost across gills

Urea

• produced in liver

• low toxicity

• must spend energy to make

• mammals excrete ____

Uric Acid

• non-toxic

• doesn’t dissolve in water, excreted as paste

• more energy to make than urea, but very little water lost with its excretion

• reptiles/birds/land snails

nephrons

• long tubules weave back and forth across cortex and medulla

• ball of capillaries = glomerulus

• Bowman’s capsule surrounds glomerulus

filtration of blood

• blood pressure forces fluid from the blood in glomerulus into Bowman’s capsule

• blood cells and large molecules stay in blood

• filtrate contains small molecules (salts, nitrogenous waste, amino acids)

blood cells and large molecules

stay in blood

• blood pressure forces fluid from the blood in glomerulus into Bowman’s capsule

antidiuretic hormone (AHD)

• made in hypothalamus, stored in posterior pituitary gland

• osmoreceptors in hypothalamus monitor blood osmolarity and regulate release of ADH

collecting ducts

receives filtrate from many nephrons

renal pelvis, ureter, bladder, urethra

filtrate flows to ____ _____ to ______ to _______ to ______

blood osmolarity

> 300 mOsm/L

salty foods

• trigger ADH release; ADH targets the collecting duct

epithelium

ADH makes __________ MORE permeable to water; water reabsorbed; urine concentrations

• results in our blood osmolarity going back to 300 mOsm/L (drink water to dilute blood)

hormone

• molecule secreted into extracellular fluid

• circulates in blood/hemolymph

• communicates regulatory messages

target cells

have appropriate receptors (for specific hormones)

• hormones maintain homeostasis

• regulate growth, development, and reproduction

hormones

maintain homeostasis

regulate growth, development, and reproduction

hormones and the endocrine system

proximal tubule

reabsorption of valuable nutrients

• ions, water

• wastes (like urea) remain in the filtrate

distal tubule

regulates [K+] and [NaCl]

ascending limb

permeable to salt, but not H20

• NaCl* is actively being transported out of the filtrate

• maintains a concentration gradient in kidney

collecting duct

• permeable to water

• water pilled out of _________ ____

• want concentrated urine, so body doesn’t loose excess water

concentration gradients

do not occur spontaneously

1. polypeptide

2. amine

3. steroid

chemical classes of hormones

polypeptide

cleavage (chopping) of longer protein chains

• water soluble

amine

made from single amino acid

• some water soluble

• some fat soluble

steroid (fat soluble)

fused C-rings derived from cholesterol

water-soluble hormones

• travel freely in the bloodstream

• bind to cell surface signal receptors

• signal transduction!

fat-soluble hormones

• travel in bloodstream bound to transport proteins

• bind to intracellular receptors (change gene transcription)

epinephrine

water-soluble amine

• liver - hormone binds to receptor in plasma membrane

• activates protein kinase (phosphate)

• activate enzyme for glycogen breakdown to glucose

estradiol

steroid (fat-soluble)

• liver cell → female bird/frog

  -

• hormone binds to intracellular receptor → activates transcription of gene for protein vitellogenin

• translation = protein in egg yolk

vitellogenin

egg yolk protein

hormones can have multiple effects

• different signal transduction pathways in different cells

• different receptors in/on cells

• ex: epinephrine

pheromones

• signaling molecule → not a hormone

chemicals release into external environment

local regulators

• signaling molecule → not a hormone

-

secreted molecules that act over short distances

-

act on target cells faster than hormones

-

ex: cytokines, nitric oxide, prostaglandin, and histamines

cytokines

immune cell communication

nitric oxide (NO)

• endothelial cells in blood vessels release NO when O2 in blood falls

• stimulates vasodilation

viagra

interferes with NO breakdown

• blood vessels stay dilated for longer

prostaglandins

• promote fever and inflammation

• aspirin and ibuprofen inhibit ______________ synthesis

pancreas

regulates blood glucose

pancreatic islets

scattered through pancreas are clusters of endocrine

• Langerhans

pancreatic islets

within _________ ____ there are two types of cells

(cluster of endocrine cells)

• alpha cells

• beta cells

alpha cells

make glycogen

which promotes the release of glucose into blood (glycogen to glucose in liver)

beta cells

makes insulin, which triggers uptake of glucose from blood; all cells respond

70-100

normal blood glucose range = __ - __ glucose/100mL

type 1 diabetes mellitus

autoimmune disorder, body destroys beta cell

• without beta cells, can’t make insulin

type 2 diabetes mellitus

• failure of target cells to respond normally to insulin

• functioning beta cells, make insulin

• body cells ignore it

• result of obsesity and lack of exercise

blood glucose

both I and II have elevated _____ ______ levels

hypothalmus

• endocrine gland in brain

• receives info from nerve throughout body and from brain

• initiates endocrine response

lymph vessels + structure

that trap foreign substances

interstitial fluid + WBCs

continually enter lymph vessles

within lymph nodes

high concentrations of defense cells

posterior pituitary

stores and secretes 2 hormones by hypothalamus

1. ADH

2. Oxytocin

oxytocin

regulates milk release during nursing (positive feedback)

-mammary glands have correct receptpr

antidiuretic hormone

helps regulate blood osmolarity