Download Chapter 20 and 21 – Human Body and Digestion/Nutrition

Biology 11A Lecture Notes – Test 3
Chapter 20 and 21 – Human Body and Digestion/Nutrition
A. Human Body
a. Organization – cells, tissues, organs, organ system, organism (Fig. 20.1)
b. Structure/Function concept (Fig. 20.5)
c. Homeostasis – staying the same
i. Model in animal systems (Fig. 20.14)
ii. Negative feedback components: control center, effector, response, stimulus (Fig.
20.15)
d. Organ systems (Fig. 20.10)
i. Digestive: take in nutrients, get rid of wastes
ii. Respiratory: exchange gases
iii. Circulatory: transport
iv. Lymphatic/immune: immunity and fluid balance
v. Excretory: rids liquid wastes
vi. Endocrine: hormone regulation
vii. Nervous: communication
viii. Integumentary: protection
ix. Skeletal: support
x. Muscular: movement
xi. Reproductive: produce offspring
B. Digestive system
a. Function: ingestion, digestion, absorption, elimination
b. Organs and parts (Fig. 21.4)
i. Mouth (Fig. 21.5)
1. Teeth to chew food.
2. Tongue with taste buds to taste food.
3. Saliva begins digestion. Lubricates food. Amylase to breakdown starch.
ii. Pharynx – epiglottis closes during swallowing, allowing food to go into
esophagus only. Choking. (Fig. 21.6a)
iii. Esophagus – muscular tube to send food to stomach. Peristalsis is muscular
contractions. (Fig. 21.6b)
iv. Stomach – stores food and also contains gastric juice (HCL, mucus, and digestive
enzymes). Ulcers. (Fig. 21.8, 21.9)
v. Small intestine – most digestion and absorption occurs here. Folded to increase
surface area (villi). Microvilli are cilia on cells that increase surface area. (Fig.
21.10b)
vi. Large intestine – absorbs water and makes feces. Appendix and infection. Colon
cancer is common, especially in low fiber diets (too slow fecal movement). (Fig.
21.12)
vii. Other organs (Fig. 21.10a)
1. Liver – makes bile (breaks down fat). Liver also involved in blood
glucose regulation, protein production, storage of minerals,
detoxification. Alcohol and drugs harm the liver.
2. Gall bladder – stores and releases bile to small intestine.
3. Pancreas – supplies small intestine with pancreatic juice (neutralizes acid
from stomach and helps digestion). Pancreas also produces insulin.
Diabetes is insulin dysfunction or insensitivity.
C. Nutrition
a. Macronutrients – needed in large amounts, energy sources (1/3 of each)
i. Carbohydrates – sugars, starches
ii. Lipids – fats, phospholipids, cholesterol
iii. Proteins – amino acids are needed to make our own protein.
b. Micronutrients
i. Vitamins – organic and help in enzyme function. Others may be antioxidants
(pick up free radicals like H2O2)
ii. Minerals – inorganic and help in enzyme function. Bone and teeth require
calcium.
c. Vegetarianism and amino acid complementation (Fig. 21.17)
d. Reading a food label (Fig. 21.20)
e. Body weight – Body Mass Index (BMI) = weight (lbs) x 703/height (in)2
i. Underweight < 19
ii. Normal 19-24
iii. Overweight 25-29
iv. Obese > 30
Chapter 22 – Respiration
A. Overview of gas exchange (Fig. 22.1)
B. Components (Fig. 22.6a)
a. Nasal cavity – air is filtered and warmed
b. Pharynx – leads to larynx
c. Larynx
i. Air direction controlled by epiglottis. When swallowing, epiglottis closes entry
into trachea. When breathing, it stays open. Choking occurs when food lodges in
trachea.
ii. Vocal cords – membrane controlled by muscles to produce voice
d. Trachea leads to bronchi, cartilage.
e. Bronchi are branched tubes of cartilage. Leads to lung
f. Alveoli is where gas exchange with circulatory system occurs. Lobular sacs. (22.6B)
C. Breathing (Fig. 22.8)
a. Inhalation – contraction of diaphragm
b. Exhalation – muscle relaxes
c. Pleural membranes surround lung and form seal.
d. Breathing is both voluntary and involuntary.
D. Gas exchange – occurs by diffusion. CO2 out, O2 in. (Fig. 22.10)
a. O2 binds to hemoglobin specifically.
b. CO2 binds to hemoglobin (20%), rest is dissolved in plasma or red blood cells. Dissolved
CO2 may be bicarbonate (HCO3-) (Fig. 22.11)
c. Carbon monoxide (CO) kills because it binds hemoglobin preventing oxygen binding.
Chapter 23 – Circulation
A. Functions and Overview
a. Pulmonary and Systemic Circuits (Fig. 23.3a)
b. Components
i. Heart – the pump
ii. Blood vessels – channels
iii. Blood – the fluid medium
c. Functions – transport (gases, nutrients, wastes, hormones). Also regulates temperature,
clotting, immunity
B. The Heart (Fig. 23.4)
a. Cardiac cycle
i. Systolic pressure – during contraction
ii. Diastolic pressure – during rest
b. Heart beat (“lub-dub”)
i. Lub – atrioventricular valve shutting
ii. Dub – semilunar valve shutting
c. Coordination – use of electrical signals (Fig. 23.5a)
i. Pacemaker
1. Sinoatrial (SA) node
2. Atrioventricular (AV) node
ii. Excitable fibers – impulses travel through here and stimulates contractions
C. Vessels (Fig. 23.7)
a. Arteries and arterioles
i. Carry blood away from heart.
ii. Thick walls, have higher blood pressure, muscles surrounding
b. Veins and venules
i. Carry blood towards heart.
ii. Thinner walls, lower pressure, less muscles
c. Capillaries
i. Exchanges nutrients and wastes with tissues
ii. Picks up carbon dioxide and releases oxygen with tissues
d. Pressure (Fig. 23.8a)
i. Blood pressure highest downstream of heart.
ii. Velocity highest in largest vessels.
iii. Measured by a cuff that cuts off main artery (Fig. 23.9)
e. Exchange at capillaries (Fig. 23.11b)
i. Arterial side – blood pressure > osmotic pressure Æ net out
ii. Venous side – blood pressure < osmotic pressure Æ net in.
D. Blood (Fig. 23.12)
a. Plasma – non-cellular portion (90%). Water, proteins, salts, nutrients, etc.
b. Cells
i. Red – carries oxygen and carbon dioxide
1. Made in bone marrow. Have no nuclei, lives only 120 days.
ii. White – immunity. Eat up bacteria, make antibodies
iii. Platelets – clotting (Fig. 23.14)
1. Wound attracts platelets causing them to bind.
2. Binding of platelets allows fibrin production.
3. Fibrin binds to platelets/wound and seals wound.
Chapter 24 – Immunity
A. Innate Immunity
a. Barriers
i. Skin – dead cells forming a protective barrier
ii. Mucous membranes – lining of digestive, urinary, and respiratory systems
1. Secretions: enzymes, acid etc. to kill pathogens
2. Mucus: traps organisms and is moved to the stomach or out the nose.
Moved by ciliary action.
b. White blood cells
i. Phagocytes eat pathogens
ii. Natural Killer Cells kill our own cells that are infected
c. Inflammatory Response – defends injuries from infection (Fig. 24.2)
i. Histamine is produce by damaged cells. This relaxes capillaries allowing greater
blood flow. This invites white blood cells and platelets. Swelling occurs.
d. Fever – raising of body temperature
i. Reduces growth rate of pathogen
ii. Stimulates phagocytes.
iii. Stimulates interferon, proteins that prepare other body cells against attack by
pathogens (Fig. 24.1b).
B. Adaptive (Acquired) Immunity
a. Overview
i. Three steps: recognize, destroy, remember
ii. Two systems: humoral (B-cell mediated) and cell-mediated (T-cell mediated)
(Fig. 24.5a)
iii. Antigen: a foreign molecule that is part of the pathogen and that the immune
system recognizes. Usually a carbohydrate or protein. (Fig. 24.6)
iv. Antibodies (Fig. 24.8)
1. Produced by B-cells and recognize specific antigens.
2. Each B-cell makes one kind of antibody. Every newly formed B-cell will
make a different kind (out of 100 million types). This gives the immune
system the ability to recognize almost any antigen.
3. Antigen binding site can bind to antigen
4. Functions: tags cells for destruction, tells other cells what kind of antigen
to look for, and stimulates other white blood cells (Fig. 24.9).
v. T-cell receptors – produced by T-cells. Same as an antibody but remains attached
to T-cells.
b. Humoral Immunity
i. First a naïve B-cell binds an antigen.
ii. Next, clonal selection of B-cell – makes more of itself and differentiates into
(Fig. 24.7a):
1. Plasma B-cells – makes and releases antibodies.
2. Memory B-cells – stored in case of attack later.
c. Cell-mediated Immunity
i. Activation involves binding and clonal selection.
ii. Cell types:
1. Cytotoxic T-cells kill infected cells or pathogens directly (Fig. 24.12)
2. Helper T-cells help stimulate more cells (Fig. 24.11)
3. Memory T-cells function like memory B-cells.
d. Vaccination (Fig. 24.4, 24.7b)
i. Tricks the immune system into immune response. This makes it easier to fight an
infection on secondary response.
ii. Mothers’ milk contains antibodies to help baby fight infections. This is passive
immunity and does not stimulate an immune response.
e. Immune Dysfunction
i. Overactive:
1. Allergies: an immune response against a harmless antigen. Histamine is
often involved.
2. Autoimmune diseases: when the immune system attacks own body. E.g.
multiple sclerosis (neural), rheumatism (joints), Lupus (DNA).
ii. Underactive: bubble-boy is missing B cells and T cells
C. HIV and AIDS
a. HIV (Human immunodeficiency virus)
i. Retrovirus that attacks CD4 Helper T cells.
ii. Life cycle (Fig. 10.20)
b. AIDS epidemiology
i. 36 million infected, 23 million dead. Transmission by bodily fluids only.
ii. Stages of disease
1. Acute phase – initial infection launches immune response. Flu-like
symptoms that pass in a few weeks.
2. Asymptomatic phase – prophage produces very little viral particles
3. AIDS – immune system depressed. High viral titer. Opportunistic
infections usually causes death.
c. Avoiding the immune response
i. Latent infection (asymptomatic phase)- very little or no RNA and protein made.
ii. High mutation rate- reverse transcriptase is very error-prone.
iii. Immune suppression- infects the immune system itself.
d. Therapies (show movie again)
i. Nucleoside analogs – mimick dNTPs that block reverse transcription. E.g. AZT,
ddI.
ii. Inhibitors of reverse transcriptase – these drugs target RT itself.
iii. Blockers of integrase – small oligonucleotides block the integration reaction.
iv. Protease inhibitors – block protease.
v. Cocktails (combination of drugs) work the best
vi. Vaccine – problem of developing because of high mutation rate of HIV.
Chapter 26 – Hormones
A. The Endocrine System
a. Overview (Fig. 26.3)
b. The endocrine system uses glands and hormones (Fig. 26.1A)
c. Hormone signaling systems (Fig. 26.2)
i. Membrane receptor signaling – uses a receptor on membrane to relay signal.
ii. Intracellular receptor signaling – signal diffuses into cell and bind receptor that
transports it to target.
B. Controlling Glands (Fig. 26.4)
a. Hypothalamus – master controller. Sends releasing hormones or inhibiting hormones to
pituitary.
b. Pituitary – sends signals to turn on other glands or to inhibit hypothalamus.
C. Some Pituitary Responding Glands
a. Thyroid – under voicebox
i. Functions: regulates metabolism by controlling oxygen consumption during
cellular respiration
ii. TRHÆTSHÆT3 and T4 (Fig. 26.4d)
iii. T3 (triiodothyronine) and T4 (thyroxine) contain iodine.
iv. Hypothyroidism (too little hormone) – slows metabolism
v. Hyperthyroidism (too much) – increase metabolism. Graves Disease (Fig. 26.5a)
vi. Goiter can be formed from too little iodine causing hypo.
b. Adrenal – on top of kidneys (Fig. 26.9)
i. Functions: response to stress
ii. Adrenal medulla (center) responds to short-term stress. Hooked up to nerves for
fast response. Epinephrine and norepinephrine increases heart rate, metabolism,
glucose release.
iii. Adrenal cortex (outside) responds to long-term stress. ACTH
(adrenocorticotropic hormone)Æ corticosteroids. These help increase blood
pressure and breakdown of proteins and fats leading to increase glucose.
D. Glucose Regulation
a. Pancreas: regulates blood glucose (Fig. 26.7)
i. Not controlled by pituitary
ii. After a meal: Insulin Æ uptake of glucose into tissues and makes liver store as
glycogen.
iii. Before a meal: Glucogon Æ makes liver breakdown glycogen into glucose and
release into blood.
iv. Diabetes: lack of insulin or inability to respond (Fig. 26.8)
1. Type 1 – autoimmune. Body attacks pancreas so that insulin is not
produced
2. Type 2 – may be due to insulin deficiency or irresponsive receptors.
More common and associated with overweight.
Chapter 27 – Reproduction
A. Male reproductive system
a. Testis Æ epididymis Æ vas deferens Æ urethra (Fig. 27.b)
b. Semen contains sperm and fluid from seminal vesicles, prostate, and bulbourethral
glands.
c. Testis structure and seminiferous tubule (Fig. 27.5).
i. Spermatogenesis: meiosis produces 4 sperm from spermatogonium.
ii. Sperm (Fig. 27.9b)
1. Head has nucleus and acrosome (contains enzymes to dissolve layers
outside the egg).
2. Midpiece is loaded with mitochondria.
3. Tail is a flagellum
d. Hormone regulation is a simple negative feedback loop (Fig. 27.4d)
i. GnRHÆ LH + FSH Æ sperm --| GnRH, LH, FSH
B. Female Reproductive system
a. Ovary Æ uterine tube Æ uterus Æ vagina (Fig. 27.3)
b. Ovary (Fig. 27.5B)
i. Oogenesis: meiosis produces four cells, only one is egg.
ii. Follicle houses oocyte.
iii. Egg matures and is released. Fimbriae draws egg into uterine tube.
iv. Follicle becomes a corpus luteum.
c. Hormone regulation is on a monthly cycle menstrual. (Fig. 27.6)
i. FSH and LH cause follicle development and ovulation.
ii. Estrogen produced by growing follicle causes spike in FSH and LH causing
ovulation.
iii. Corpus luteum produces progesterone and estrogen which maintain uterine
lining.
iv. If no pregnancy, then corpus luteum degrades Æ less E and PÆ uterine lining
sloughs off (menstruation).
v. If pregnancy, then HCG from the placenta keeps corpus luteum alive, uterine
lining maintained.
C. Copulation (Fig. 27.4c)
a. Male
i. Erection – arteries dilate, veins collapse in penis. cGMP allows blood flow into
erectile tissue. Viagra prevents cGMP breakdown.
ii. Ejaculation – stimulation of nerve tissue in penis causes movement of sperm
from epididymis. Semen is mixed and contractions at base of penis force semen
out. 300-400 million sperm.
iii. Orgasm is ejaculation and arousal of pleasure centers in brain.
b. Female – female orgasm does not move egg. Clitoris contains nerve center. Labia
become engorged during arousal.
D. Fertilization (Fig. 27.9c)
a. Sperm releases enzymes from acrosome which dissolves egg layers.
b. Head of sperm fuses with membrane, nucleus fuses with egg nucleus
c. Other sperm are blocked by chemicals reinforcing membrane and layers outside of egg.
E. Human development
a. Fertilization occurs in uterine tube. Implantation occurs at 1 week (Fig. 27.15a)
b. Placenta (Fig. 27.15b-f)
i. Forms from chorion which produces HCG to maintain estrogen and progesterone
to maintain uterus and stimulate mammary glands.
ii. Exchanges materials between mother and fetus.
1. No blood exchange
2. Materials exchanged at capillaries of chorionic villi. Wastes and carbon
dioxide out, nutrients and oxygen in.
c. Birth (Fig. 27.17b)
i. Uterine muscle stretching as fetus grows causes contractions.
ii. Positive feedback loop: contractions cause oxytocin to be released, which causes
more contractions. Dilation of cervix also releases oxytocin.
iii. Contractions finally expel baby.
iv. Afterbirth (placenta and uterine lining) follows shortly.
F. Birth Control (Fig. 27.8)
a. Surgery
i. Vasectomy – in males. Vas deferens are cut and tied. Can be reversed. Safer
than:
ii. Tubal ligation – in females. Uterine tubes are tied. Permanent.
b. Temporary
i. Barrier methods
1. Prevent entry of sperm. Condoms, cervical caps, spermicide etc.
2. Block implantation - IUD is a shield that blocks embryo from uterus
ii. Hormone regulation
1. “The Pill” – continuous supply of estrogen and progesterone prevents
ovulation, lowering near end of cycle forces menstruation. Others:
norplant, depoprovera.
2. “Morning after pill” causes menstruation, even with implantation.