Transcript Review for Exam 3

Review for Exam 3
Friday 7th December 2007
Regulation of gene
expression
Pancreas
cell
Eye lens cell
(in embryo)
Nerve cell
Glycolysis
enzyme
genes
Crystallin
gene
Insulin
gene
Hemoglobin
gene
Key:
Active
gene
Inactive
gene
Figure 11.3
How do we develop?
• On ovulation day, egg and sperm fuse to form zygote.
• Zygote divides, implants onto uterus and grows into Embryo
and hangs out for about 9 months.
• Embryo decides it is time to breathe air, fetal adrenal glands
trigger contractions and out comes baby.
• Baby grows grows grows into child, child undergoes
puberty and becomes adult.
• Adult lives, works, reproduces (perhaps), gets gray hair and
croaks.
REMEMBER!!!!!!!!!
• If viable sperm contact an egg at the time of
ovulation fertilization will occur.
• This “typically” occurs on day 14. Remember Day
1 is first day of menstruation.
• The fertilized egg will implant on day 6.
• The new embryo will begin to produce HCG-Human Chorionic Gonadotripin.
• HCG maintains the corpus luteum and allows the
production of progesterone and estrogen until the
placenta takes over this task.
•
Remember Fertilization
Egg must develop and be released
on ovulation day.
• Egg must be correctly positioned in
the oviduct and attract sperm.
• Vaginal tract must activate sperm.
• Hormonal levels must be exact.
• Ensure only one sperm joins with
egg.
Remember - Fertilization
• Sperm must undergo
capacitation--process of
activation by substances in
female vaginal tract fluids.
• Sperm motor from vagina up
through cervix, uterus, to the
oviduct.
• Many sperm attempt
fertilization, only one
succeeds (except for twins).
Development before
Implantation
• Fertilization
• Cleavage: successive rounds
of cell division. A one cell
zygote--2 cell--4 cell--8 cell-.
• Cleavage occurs in the
oviduct.
• Morula: 16 cell stage--enters
the uterus.
• Key cell differentiation step:
– Trophoblast
– Inner Cell Mass
Development before
Implantation
• Blastocyst
• Hollow ball of cells.
• Each cell is called a blastomere.
• Inner cell mass--become the
embryo.
• Trophoblast--Incredible Altruistic
Cells!
– Escape from the Zona
Pellucida
– Digest through Endometrium
– Initiate HCG secretion
– Form the Placenta
Gastrulation
• Truly the most important day of
your life!
• Process of forming 3 germ layers-this process requires cell
movement.
• Each germ layer forms specific
tissues and organs
– Ectoderm--(blue)--will form
skin and nervous system.
– Mesoderm--(red)--will form
muscles, kidneys, connective
tissue, and reproductive organs.
– Endoderm--(yellow)--will form
digestive tract, lungs, liver and
bladder.
Figure 12.8b
Drugs and addiction
• Drug addiction is a condition characterized by compulsive
drug intake, craving and seeking, despite negative
consequences associated with drug use.
• The activity of any drug varies with dose
– The amount of the drug taken over time
• The amount of a drug taken to be toxic or lethal depends
upon the chemical structure of the drug
– Also body size and other physiological variables
The Respiratory System
• During inspiration or inhalation, air is conducted
toward the lungs.
• During expiration or exhalation, air is conducted
away from the lungs.
• Works in conjunction with the cardiovascular
system for RESPIRATION to occur
• Breathing –air in and out of lungs
• External respiration –exchange of gasses between air &
blood
• Internal respiration – exchange between blood &tissue fluid
• Cellular respiration –production of ATP in cells
The Respiratory System
• Two parts:
• Upper Respiratory Tract
• Nasal Cavities
– Filter, warm and moisten air
• Pharynx
– Connection to surrounding
regions
• Glottis
– Passage of air into larynx
• Larynx
– Sound production
The Respiratory System
• Lower Respiratory Tract
• Trachea
– Passage of air to Bronchi
• Bronchi
– Passage of air to lungs
• Bronchioles
– Passage of air to each
alveolus
• Lungs
– Gas Exchange
The Trachea
• Windpipe – connects
larynx to primary bronchi.
• Held open by cartilage
• Goblet cell
– Makes mucus
• Mucosa contains layer of
pseudostratified ciliated
epithelium
– Sweep dirt and excess
mucus upwards
The Bronchial Tree
• The trachea divides
into L & R primary
bronchi
– eventually branch
into secondary
bronchi and then into
bronchioles.
– Each bronchiole
leads to an elongated
space enclosed by
alveoli.
The Lungs
• These lie on either side of the heart within the
thoracic cavity.
• Total cross-sectional area of 50 – 70 meter
squared (1 ½ Tennis courts)
– Right lung has three lobes and the left lung has two
lobes.
• This allows room for the heart
– Each lobe is divided into lobules, further divided into
bronchioles serving many alveoli.
Alveoli
• There are 300 m alveoli per set
of lungs.
– Each one is made up of
squamous epithelium and
blood capillaries.
• Gas exchange occurs: O2
diffuses across the alveolar wall
and enters blood – CO2 goes in
other direction
• Lined with lipoprotein – lowers
surface tension and prevents
them from closing.
Mechanism of Breathing
• Respiratory Volumes
– Tidal volume is the amount of air that moves in
and out with each breath.
– Vital capacity is the maximum amount of air that
can be moved out in a single breath.
• Inspiration can be increased by expanding the chest
(inspiratory reserve volume).
– Residual volume is the air remaining in the lungs
after deep exhalation
Gas Exchanges in the Body
• External respiration refers to gas exchange between
air in the alveoli and blood in the pulmonary
capillaries.
– Blood entering the pulmonary capillaries has a HIGHER
partial pressure of CO2 than atmospheric air.
• CO2 diffuses out of the blood into the lungs.
• Carried in blood plasma as bicarbonate ions (HC03 ions)
– Blood entering the pulmonary capillaries has a LOWER
partial pressure of O2 than the avlvoli.
• O2 diffuses into plasma and then red blood cells
• Binds with hemoglobin – forms oxyhemoglobin
Internal Respiration
• Internal respiration - gas exchange between the
blood in systemic capillaries and the tissue fluid.
– O2 diffuses out of the blood into the tissue because the
partial pressure of O2 in tissue fluid is LOWER than
that of blood.
• O2 leaves hemoglobin and enters tissue fluid
– CO2 diffuses into the blood from the tissue because
the partial pressure of CO2 in tissue fluid is HIGHER
than that of blood
• Internal Respiration
occurs at systemic
capillaries – that is in
the major organs.
• External Respiration
occurs at pulmonary
capillaries – that is in
the lungs ONLY
Addiction
• Ventral tegmental area (VTA)
– Thought to be positive enforcement
area (pleasure center).
– Experiments on rats and rhesus
monkeys have show that both would
rather electrically stimulate this area of
the brain than eat – even if near to
starvation
• Nucleus accumbens (NA)
– joined to the VTA by synaptic
connections
– Interprets the stimulation signal from
the VTA
Addiction
• Frontal cortex (FC)
– Play a part in impulse control,
judgment, language production,
working memory, motor function,
problem solving, sexual behavior,
socialization and spontaneity.
– Assist in planning, coordinating,
controlling and executing behavior.
– This is why behavioral changes
occur which are hard to break
Addiction
• Opiates, marijuana, caffeine,
and alcohol all produce VTA
self-reinforcing effects.
• Drugs of abuse take over the
neuronal circuitry involved in
motivation and reward, leading
to altered engagement of
learning processes.
• Because of this, drug-associated
cues can trigger cravings as well
as unconcious or compulsive
drug-seeking behavior, with the
sense that voluntary control
over drug use is lost
Addiction
• Objects, people or places also seem to to be strongly
associated with the drug experience, making them 'Triggers'
to 'Cravings'
– increase the chances of further use.
• Animal studies have shown drug availabilty over and above
the actual effects of the substance) are associated with
stimuli, exposure to objects associated with use trigger the
release of adrenaline (Fight or flight)
– this excitation can be perceived as a 'need' to use
Addiction
• Users in addictive drugs in
the US in 1991
• The top three are widely
not considered drugs by
most of the population
• All of these three produce
addictive behavior.
Primary Lymphatic Organs
• Lymphatic organs contain
large numbers of
lymphocytes (White
Blood cells).
• Primary organs are:– Red Bone Marrow.
• Site of stem cells.
– Source of B lymphocytes.
– Thymus Gland.
Lymphocytes from bone
marrow pass through to
form T-lymphocytes
• Produces thymic hormones
(thymosin).
• Aids in T lymphocyte
maturation.
Secondary Lymphatic Organs
• Secondary lymphatic organs are places
where lymphocytes encounter and bind
with antigens.
– Spleen.
– Lymph nodes.
– Tonsils.
– Peyer’s patches.
Secondary Lymphatic Organs
• Spleen – upper left of
abdominal cavity behind
stomach. Sectioned off by
connective tissue- white pulp
& red pulp.
– White pulp – lymphocytes
– Red pulp – filters blood.
Blood entering the spleen
passes through red pulp
before it leaves (network
of sinuses)
– FRAGILE
Secondary Lymphatic Organs
• Lymph Nodes – occur
along lymphatic vessels.
Formed from connective
tissue.
– Packed full of Blymphocytes
– As lymph courses
through sinuses it is
filtered by
macrophages, which
engulf pathogens and
debris.
– Also present- Tlymphocytes – fight
infection and attack
Secondary Lymphatic Organs
• Tonsils – patches of
lymphatic tissue.
• Perform the same
function as lymph nodes
– First line of defense
• Peyer’s Patches – on
the intestinal wall and
appendix. Attack
pathogens that ender the
body by way of the
intestinal tract.
Innate Immunity
• One important function of the immune system is to
promote growth and repair after injury
– Either via physical damage or microorganisms
• The mobilization of innate immune cells to get rid of
damaged cells or microorganisms is called
inflammation
• Small molecules called cytokines are also involved
T Cells
• Provide cell-mediated immunity.
• Produced in bone marrow, mature in thymus.
• Antigen must be presented in groove of HLA
molecule.
• Cytotoxic T cells destroy non-self proteinbearing cells.
• Helper T cells secrete cytokines that control
the immune response.
B Cells
• Provide antibody-mediated immunity against
bacteria.
• Produced and mature in bone marrow.
• Reside in spleen and lymph nodes.
– Circulate in blood and lymph.
• Directly recognize antigen and then undergo
clonal selection.
• Clonal expansion produces antibody-secreting
plasma cells and memory B cells.
Clonal selection Theory
• The antigen selects which
lymphocyte will undergo
clonal expansion and
produce more lymphocytes
with the same type of
antigen receptor.
– Some become memory
cells – long term
immunity to the same
infection.
– B-cells become plasma
cells – fight infection
– Apoptosis – when
danger of infection is
over, all plasma cells
Antibodies
• Classes.
– IgG - Enhances phagocytosis.
– IgM - Activates complement proteins.
– IgA - Prevents attachment of pathogens.
– IgD - Antigen receptors on virgin B cells.
– IgE - Immediate allergic response.