Download Ch 43-45 PPT

Immune System
Ch 43
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Human Body has 3 lines of defense
1) Nonspecific defense – unspecialized, general defense against all
 Ex. Skin, cilia, gastric juices, mucus
2) 2nd line of nonspecific defense
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Phagocytes = WBC, engulf pathogens by phagocytosis
(neutrophils)
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Complement rxns – proteins, help phagocytes kill microbes
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ex. interferons – released by cells to attack viruses
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Inflammation – ex. histamine – releases phagocytes
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3) Immune response – v. specific
 antigens = foreign invader, signal production
of antibodies
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Lymphocytes
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= WBC, primary agent in the immune response
made in marrow, concentrate in lymph, thymus and
spleen
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Types of WBC
1) B cells – made in the bone marrow, binds to antigens
(specific)
 antibodies = proteins, specific to an antigen, video
 Y shaped, bind to antigens, then phagocytes engulf
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5 classes called immunoglobins
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plasma cells - B cells that release specific antibodies
memory cells - long lived B cells, respond to old
invasions, immunity (10-17 days after primary invasion)
– p846
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2) T cells – made in marrow but mature in the thymus
 helps in differentiation between self and nonself cells, MHC
judges self cells, if sees an invader it makes:
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killer T cells - attacks foreign cells, causes them to lyse
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helper T cells - makes more B and killer T cells
video
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2 types of immune system reactions – *p848
1) cell-mediated - T cells responds to any non self cell and
bind
2) humoral or antibody mediated response - involves most
cells by responding to antigens or pathogens in the
blood
 B cells then make memory cells for immunity
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Disease treatment
1) use antibodies derived from bacteria
2) vaccines- weak pathogens, stimulate memory cells
3) ? autoimmune diseases – fights self cells, Lupus,
MS
4) Immunodeficiency disease – major immune failure,
SCID mice, HIV
 HIV- CD4 T cells depleted, retrovirus – so DNA into
host’s genome
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Homeostasis
Ch 44
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Thermoregulation
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= regulation of body temperature
Ectotherms: body heat from their
environment, cold-blooded, ex. amphibians,
fish
Endotherms : generate body heat,
homeotherms or warm-blooded = maintain a
constant temperature
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Mechanisms for temp. regulation
1) Evaporation = losing water to cool the body
2) Warm by metabolism - muscles contract and
metabolic activities generate heat, ex. shivering
3) Adjusting surface area to regulate temperature
 Vasodilatation = increase blood flow to an area, heat
lost
 Vasoconstriction – decrease blood flow, reduces
heat loss
 also: hibernation, migrate, hair, feathers, blubber
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Excretory System
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= homeostasis by regulating water & removing bad
wastes
Osmoregulation = absorb and excrete water and
dissolved substances to maintain water balance
ex. Marine fish - water is lost by osmosis, so must
constantly drink, rarely urinate, and secrete salts via
gills
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Some mechanisms:
1. Contractile vacuoles -pump water out, Paramecia
2. Malpighian tubules – tubes that empty into the
digestive track, wastes are excreted, insects
3. Vertebrate kidney – filtering tubes called nephrons,
collect waste, passes through ureters to the bladder
for storage, urine excreted through the urethra
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Path – p883
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Nephron contains the glomerulus which is a
ball of capillaries surrounded by Bowman’s
capsule
Blood from renal artery enters here, goes
through proximal tubule where secretion and
absorption occurs and returns via renal vein
To Loop of Henle : water and salt reabsorbed
To distal tubule: more secretion and
reabsorbing
To collecting duct – excess salt and water out
via urine in ureter
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3 processes of the Nephron:
1. Filtration- nonselective, small material in the
blood, 1-2 L a day
2. Secretion- in tubules, selective, ex. ph
3. Reabsorption –proximal and distal tubules
and loop of Henle, reabsorb most of the
“good” material and water
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Ridding of waste usually
involves ridding of nitrogen,
which can become toxic
Aquatic animals excrete
ammonia directly into the
water
Mammals convert NH3 to
urea in their livers. Urea is
less toxic and requires less
water to excrete in the
urine
Birds, insects, reptiles
convert urea to uric acid =
insoluble in water, solid.
Need less water to excrete.
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Hormones
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Antidiuretic hormone (ADH) – increases the
reabsorption of water
Aldosterone - increases reabsorption of water
and Na+
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Endocrine System
Ch 45
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Function: make hormones to maintain
homeostasis
Hormone = chemical produced in one part of
the body that affects cells elsewhere →
transported via blood
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Hypothalamus—monitors the external/internal conditions
- stimulates hormones via neurosecretory cells, link
hypothalamus and the Pituitary gland (master gland),
found a the base of the hypothalamus.
Posterior pituitary = makes ADH, oxytocin
Anterior pituitary = produces growth hormone, FSH, LH,
TSH, endorphins
Thyroid → calcitonin (Ca++), thyroxin, metabolism control
Pineal – melatonin (circadian)
Adrenal → epinephrine, norepinephrin, fight/flight rxns
Thymus → T cells, immunity
Gonads → androgens, estrogens, sexual development/function
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Regulation of blood glucose
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common feedback loop
pancreas contains cells called islets of Langerhans, that
makes alpha and beta cells,
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Beta cells secrete insulin→ if blood glucose rises,
beta cells secrete insulin→ insulin stimulates cells to
absorb glucose→ cells convert glucose to glycogen
or fat → glucose concentration decreases
Alpha cells secrete glucagon→ if blood glucose
drops, alpha cells secrete glucagon → glucagon
stimulates the liver to release glucose (breaks down
glycogen)
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