Lisa Numann - Topic 5

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Topic 5

5.1.1 Explain why digestion of large food molecules is essential.

Organic food material is composed of macromolecules.
proteins
fats
carbohydrates
Macromolecules are too large to cross the membranes and enter animal cells.
Through digestion they are made small enough to absorb into the blood system and can move into cells.

5.1.2 Explain the need for enzymes in digestion

increases rate of digestion.
if food would break down on its own it could take days instead of hours.
enzymes use hydrolysis to break bonds.
they reduce the amount of activation energy needed to start the hydrolysis of macromolecules.

5.1.3 State the source, substrate, products and optimum pH conditions for one amylase, protease and lipase.

Pancreatic amylase
source: pancreas
substrate: maltose
product: glucose
optimum pH: neutral
Pepsin
source: stomach
substrate: polypeptides
products: smaller polypeptides/dipeptides
optimum pH: 1.8-3.2
Lipase
source: pancreas
substrate: lipid
product: glycerol & fatty acid
optimum pH: 7.8

5.1.4 Draw a diagram of the digestive system including mouth, esophagus, stomach, small intestine, large intestine, anus, liver, pancreas, gall bladder.

5.1.5 Draw a villus in vertical section.

5.1.6 Define absorption

absorption: taking in of chemical substances through cell membranes or layers of cells. 

5.1.7 Explain the concept of a balanced diet

bioenergetics: study of the acquisition of energy.
calorimetry: total amount of energy released when bonds of organic molecules are broken. 
Energy potential of food is expressed in calories per gram.
Lipids energy release > proteins energy release > carbohydrates energy release
BMR (basal metabolic rate): minimum resting energy expenditure of an awake alert person.
Balanced diet consists of
equal energy with expenditure.
ingredients necessary to maintain homeostasis
ingredients that include adequate substrates for energy generation
ingredients that have the essential nutrients to replace those lost in urine. 
Members of all 6 food groups (dairy, meats, vegetable, fruit, grain, fats)

5.1.8 Explain the importance of vitamins and minerals

vitamins
maintain epithelia cells
synthesis retinal
normal bone growth
calcium and phosphorous absorption
NAD and FAD
Acteyl CoA
minerals
needed for normal membrane function
normal muscle & neuron function
normal bone structure
hemoglobin

5.1.9 Outline one health problem concerned with malnutrition.

Eating disorders: Anorexia nervosa and bulimia
Anorexia: self-induced starvation
high achievers attempting to reach ideal weight
symptoms: dry skin, abnormally low heart rate, reduction in bone & muscles mass, cessation of menstrual cycles
Bulimia: feeding binges followed by vomiting, laxative use or both. 
eating binge followed by induced vomiting, commonly accompanied by the use of laxatives.
Health risks: cumulative damage to stomach, esophagus, oral cavity and teeth, electrolyte imbalances, diarrhea.

5.2.1 Describe the action in the heart by terms of collecting of blood:

heart has 4 chambers
2 upper atria (receive blood)
2 upper ventricles (push blood out)

5.2.2 Draw a diagram of the heart showing all four chambers, associated blood vessels and valves.

5.2.3 Outline the way the heart beats and is regulated in terms of the myogenic nature, nerve and hormone stimulation. Outline the mechanisms that control the heartbeat including SA node and conducting fibers in the ventricular walls.

the heart = cardiac muscle tissue
action potential/impulse involves depolarization of the membrane with Na+ channels opening. 
Certain cardiac muscles cells can automatically initiate their own action potential.
SA node starts the heart’s beat and is located in the right atria.
The force of a heart beat is dependent on how much blood is returned by the veins.
Stroke Volume: amount of blood pumped out of the ventricles with each contraction. 

5.2.4 Explain the relationship between the structure and function of arteries, capillaries and veins.

Arteries:
more muscular
take blood away from heart
Capillaries
smallest vessels
exchange CO2 & O2
Veins
larger than arteries
return blood to heart

5.2.5 State that blood is composed of plasma, erythrocytes, leukocytes and platelets.

5.2.9 State that the blood transports the following: heat, nutrients, O2, CO2, hormones, antibodies and waste products.

5.2.7 Outline one health problem concerned with disorders of the transport system.

mononucleosis
highly contagious viral disease
caused by Epstein-Barr virus
Excessive number of leucocytes and lymphocytes
Symptoms: being tired, achy, chronic sore throat, low-grade fever
No cure, recovery is complete

5.3.1 State that disease can be caused by a variety of organisms.

virus, bacteria, fungi, protozoa

5.3.2 Explain how skin and mucus membranes act as barriers against microbes.

pathogens encounter the body’s first defense = skin
second defense is secretions of mucus, sweat, tears and saliva.
Mucus traps microbes due to its thickness.

5.3.3 Outline phagocytic leucocytes ingest disease-causing organism in blood and in body tissues.

slow and unselective line of defense
chemicals released attracts macrophages.

5.3.4 State the difference between antigen and antibody.

antibody: soluble globular proteins that recognize antigens produced by plasma B cells
antigen: proteins/lipids/polysaccharides/nucleic acids located on pathogen. 

5.3.5 Explain the antibody production.

pathogen invades body
pathogen engulfed by macrophage
antigen presented on the macrophage
helper T cell interacts with B cells
specific B cells contacted
b cells divide into plasma B cells
plasma B cells form produce antibodies

5.3.6 Outline the effect of HIV on the immune system.

immune responses impaired by gradual destruction of helper T cells
ordinarily harmless pathogens can initiate lethal infections since the immune system is so depressed

5.4.1 Describe four features of alveoli that allow them to carry out gas exchange efficiently.

increases surface area for absorption of O2 and CO2
surfacent (substance) lowers surface tension of H2O
1 cell layer thick, helps diffusion
lots of capillaries

5.4.2 Explain the necessity for a ventilation system

cells require continuous supply of O2
as cells use oxygen, CO2 is given off
air is removed in and out of lungs through ventilation system (breathing)

5.4.3 Draw a diagram of the gasexchange system including trachea, bronchi, bronchioles and lungs.

5.4.4 State the difference between breathing and cellular respiration:

breathing: intake & exhalation of air from the lungs
cellular respiration: breaking down of glucose to release energy for ATP synthesis. 

5.4.5 State that exercise improves the functioning of the heart and lungs.

5.4.6 Explain how and why breathing rate varies with exercise.

chemosensors send impulses to the breathing center of the brain
nerve impulses sent to diaphragm and intercoastal muscles to increase contraction.

5.5.1 Define homeostasis

homeostasis: dynamic state of equilibrium, a regulation between internal environment and external environment.

5.5.2&.5.5.3 Explain the concept of homeostasis with reference to body temperature and levels of blood glucose. Explain the concept of negative feedback. (i) negative feedback: depressing stimuli cause variable to change in direction opposing that of initial change.

5.5.4 State the nerve and the endocrine systems are involved in homeostasis.

Two body systems that involve communication: nervous and endocrine.

5.5.5 State that the nervous system consists of the central nervous system and peripheral nerves composed of the special cells called neurons that can carry electrical impulses rapidly.

Organs that pick up stimuli, analyze and respond to stimulus.
Examples: 
brain
spinal chord
sense organs
peripheral neurons (nerve cells outside organs leading in &out of organs)

5.5.6 State that the endocrine system consists of glands, which release hormones that are transported in the blood.

Internal organs that secret hormones
Examples:
pancreas
testes
ovaries
thyroid
pituitary
hypothalamus
adrenal
thymus

5.5.7 Define excretion

excretion: the removal of toxic waste products of metabolism from an organism.

5.5.8 Define osmoregulation. State the functions of the kidney are excretion and osmoregulation.

osmoregulation: the control of the osmotic and water potential ina cell or inside a living organism.

5.6.1 Explain that sexual reproduction promotes variation in a species.

5.6.2 Draw diagrams of the adult male and female urinogenital systems.

5.6.3 Explain the role of hormones in regulating the changes of puberty.

 * FEMALES
Menstrual cycles: FSH, LH, estrogen and progesterone control the cycle.
LH and FSH are released from the pituitary, which stimulates the ovary to secrete estrogen.
LH triggers ovulation.
Estrogen makes cervix excrete clear mucus; medium for sperm travel.
FSH causes follicle to mature. And ovaries to secrete estrogen.
LH stimulates formation of corpus luteum.
 *MALES
Testosterone stimulates spermatozoa production, formation of reproductive organs and secondary sex characteristics.
LH stimulates testosterone production
FSH stimulates sperm formation. 

5.6.4 List secondary sexual characteristics in both sexes

males: pubic hair, facial hair, deepening of voice, oilier skin
females: pubic hair, breast development, oilier skin, growth of hips

5.6.5 State the difference between copulation and fertilization.

Fertilization: fusion of sperm with egg nucleus to restore diploid chromosome number. 
Copulation: erection of penis, ejaculation, propulsion of semen from male duct system. 

5.6.6 Describe early embryo development up to the implantation of the blastocyst.

several mitotic cleavages to form solid ball of cells called a morula
further divisions to form hollow blastocyst

5.6.7 State that the fetus is supported and protected by the amniotic sac and amniotic fluid.

5.6.8 State that materials are exchanged between the maternal and fetal blood in the placenta.

5.6.9 Outline the process of birth and its hormonal control including progesterone and oxytocin.

dilation of the cervix: from the onset of labor until the cervix reaches full diameter.
expulsion stage: time from full dilation until delivery
delivery of placenta/afterbirth
decreasing progesterone & estrogen and increasing oxytocin reduce uterus to normal size.
Nipples stimulate production of oxytocin.
Oxytocin and prolaction trigger production of milk.

5.6.10 Describe four methods of family planning.

abstention
diaphragm
condoms
IUDs
the Pill

5.6.11 Discuss the ethical issues of family planning and contraception.

prevents birth of unwanted children
avoidance of genetic diseases
impact on biosphere reduced
religious beliefs disagree with intervening with natural process
promiscuity encouraged
killing of new potential human lives

5.6.12 Outline the techniques of amniocentesis and choronic villus sampling.

diagnoses chromosomal abnormalities
choronic villus sampling: removal of tissue from vagina. 
amniocentesis: withdrawing amniotic fluid containing embryonic cells

5.6.13 Outline the process of in vitro fertilization

ovaries are stimulated to develop many follicles
eggs made mature in follicles through hormones
semen sample provided
eggs extracted
fertilization occurs in dish
two/three embryos selected & placed in uterus

5.6.14 Discuss the ethical issues of IVF.

childless couples can have children
screening of embryos promotes avoidance of genetic diseases
inherited forms of infertility passed on
excess of embryos produced
humans choose which embryos are “good”
multiple birth’s risks