2. REQUIREMENTS
• 2 EXAMINATIONS
– INTRO TO HOMEOSTASIS
– REPRODUCTION TO MAN & ENVIRONMENT
• GROUP PROJECT
– 10‐MINUTE VIDEO OF AN ASSIGNED TOPIC
• QUIZZES, ASSIGNMENTS, SURPRISES
9. BIOGEOCHEMICAL THEORY
• Origin of life on earth is
the result of a slow and
gradual process of
chemical evoluMon that
probably occurred about
3.8 billion years ago
• proposed independently
by: Oparin, a Russian
scienMst in 1923 and
Haldane, an English
scienMst, in 1928
10. ALSO KNOWN AS THEORY OF CHEMICAL EVOLUTION
• Spontaneous generaMon of life, under the present
environmental condiMons is not possible
• Earth's surface and atmosphere during the first billion years
of existence, were radically different from that of today's
condiMons
• The primiMve earth's atmosphere was a reducing type of
atmosphere and not oxidising type
• The first life arose from a collecMon of chemical substances
through a progressive series of chemical reacMons
• Solar radiaMon, heat radiated by earth and lighMng must
have been the chief energy source for these chemical
reacMons
11.
12.
13.
14.
15.
16. THEORY OF SPONTANEOUS
GENERATION
• This theory assumed that
living organisms could
arise suddenly and
spontaneously from any
kind of non‐living maher
• One of the firm believers
in spontaneous
generaMon was Aristotle,
the Greek philosopher
(384‐322 BC)
17. LIFE FROM NON‐LIFE???
• dead leaves falling from a tree • Supporters: Descartes, Galileo and
into a pond would transform Helmont supported this idea
into fishes and those falling on
soil would transform into
worms and insects • Von Helmont: prepared a 'soup'
from which he could
spontaneously generate rats
• insects develop from morning – The 'soup' : dirty cloth soaked in
dew and rojng manure water with a handful of wheat
grains; if human sweat is added as
an 'acMve principle' to this, in just 17
• mud of the Nile river could days, it could generate rats
spontaneously give rise to
many forms of life
• The idea of spontaneous
generaMon was popular almost
Mll seventeenth century
18. LIFE FROM NON‐LIFE???
• The theory of Spontaneous GeneraMon was
disproved in the course of Mme due to the
experiment conducted by:
– Fransisco Redi, (1665)
– Spallanzani (1765)
– Louis Pasteur (1864) in his famous Swan neck
experiment
• This theory was disapproved, as scienMsts gave
definite proof that life comes from pre‐exisMng
life
20. SPALLANZANI’S EXPERIMENT
• placed broth in eight
containers
– four with cork
– four with air Mght tops
– RESULTS: the air Mght
containers had no
microbes( cloudiness); the
four corked vessels showed
organisms
– CONCLUSION: did not
disprove spontaneous
generaMon but strengthened
the case against it
22. INTERPLANETARY OR COSMOZOIC
THEORY
• Life has reached this • The theory did not gain
planet Earth from other any support
heavenly bodies such as
meteorites, in the form of
highly resistance spores • This theory lacks
of some organisms evidence, hence it was
discarded
• This idea was proposed
by Richter in 1865 and
supported by Arrhenius
(1908) and other
contemporary scienMsts
23. SPECIAL CREATION THEORY
• According to this theory, all the
different forms of life that occur
today on planet earth, have been
created by God, the almighty
• This idea is found in the ancient
scriptures of almost every religion
• According to Hindu mythology, Lord
Brahma, the God of CreaMon,
created the living world in
accordance to his wish
• According to the ChrisMan belief,
God created this universe, plants,
animals and human beings in about
six natural days
24. SPECIAL CREATION THEORY
• The Sikh mythology says that all forms of life including
human beings came into being with a single word of
God
• Special creaMon theory believes that the things have
not undergone any significant change since their
creaMon
• The theory of Special CreaMon was purely a religious
concept, acceptable only on the basis of faith
• It has no scienMfic basis to date…
27. THE CHARACTERISTICS OF LIFE
1 Life has OrganizaMon
2 Life Acquires Materials and Energy
3 Life Stays Just About the Same
4 Life Responds to SMmuli
5 Life Reproduces
6 Life Grows and Develop
7 Life Adapts
28. ORGANIZATION
• Living things are
organized
• Their parts are
specialized for specific
funcMons
• Note: water contains H
and O = 50% of a cell’s
weight
29. METABOLISM
• Living things take
materials and energy
from the environment
• They need an outside
source of nutrients
• Energy = capacity to do
work )maintain the
organizaMon of the
cell)
35. VARIATION, CHANGE AND
EVOLUTION (ADAPTATION)
• Living things are adapted
• They have modificaMons
that make them suited to a
parMcular way of life
• AdaptaMon: modificaMons
that make an organism
suited to its way of life
• EvoluMon: process by which
characterisMcs of species
change through Mme
40. SOME EXAMPLES OF CELLULAR
PROCESSES
• Cellular CommunicaMon
– Cell signalling
– Nervous response or endocrine response (ANIMALS)
– “Phytohormones” and for root development
• DNA repair
– Response to damage of geneMc material
• Gene Expression
– Genes for turning “ON” and “OFF”
• Metabolism
– Overall cellular chemical reacMons (anabolic or catabolic)
• Programmed Cell Death or Apoptosis
51. • Programmed cell death
APOPTOSIS
• the body's normal method
of disposing of damaged,
unwanted, or unneeded
cells
• important for sculp5ng
5ssue and organ structure
during development of the
embryo, but may occur at
any Mme even in adult cells
when a Mssue needs to be
remodeled (damage
repair)
52. THE CELL
• The cell is considered to be the smallest structure
in biology
• Understanding of cells and the basics of cell
structure and funcMon is criMcal to making sense
out of biology
• LimitaMons of the human eye: early biological
research concentrated on developing tools to
help us see very small things (LEEUWENHOEK)
55. THE CELL: PROKARYOTES VERSUS
EUKARYOTES
• The common features of prokaryoMc and
eukaryoMc cells are:
• DNA (geneMc material)
– located in a non‐membrane bound nucleoid
region in prokaryotes and a membrane‐bound
nucleus in eukaryotes
• Plasma membrane (phospholipid bilayer with
proteins that separates the cell from the
surrounding environment)
– a selecMve barrier for the import and export of
materials
• Cytoplasm
– consists of a fluid porMon called the cytosol and
the organelles and other parMculates suspended
in it
• Ribosomes
– protein synthesis takes place
65. 1. MERISTEMATIC TISSUES
• Examples: apical meristem; lateral meristem,
intercalary meristem, etc
• Tissues composed of immature,
undifferen_ated cells capable of cell division
– formed exclusively by undifferenMated or
embryonic cells
• Found in rapidly growing parts of the plant
– responsible for bringing about growth of the plant
body due to their capacity to undergo conMnuous
mitoMc divisions
68. • Nature:
– Cells equally expanded on all
sides; oval, round, polygonal or
elongated
– cell walls are thin and made of
cellulose
– May contain chlorophyll
(Chlorenchyma)
• Occurrence:
– cortex of root, ground _ssue in
stems and mesophyll of leaves
• Func_on:
– Store and assimilate food
– Give mechanical strength by
maintaining turgidity
– Store waste products like tanin,
gum, crystals and resins
69. • Nature
– The cells are elongated and
are circular, oval or polygonal
in cross‐sec_on
– Cell wall is unevenly thickened
with cellulose at the corners
against the intercellular spaces
• Occurrence
– Found under the skin i.e.
below the epidermis in dicot
stems
• Func_on
– Provide mechanical support to
the stem
– Being extensible, these cells
readily adapt themselves to
the rapid elonga_on of the
stem
71. SCLERENCHYMA
• Nature
– The cells are long, narrow, thick and lignified, usually pointed at both
ends
– The cell wall is evenly thickened with lignin and some_mes is so thick
that the cell cavity or lumen is absent
– Nucleus is absent and hence the _ssue is made up of dead cells
– They have simple, ogen oblique pits in the walls
– The middle lamella i.e. the wall between adjacent cells is
conspicuous
• Occurrence
– Found abundantly in stems of plants like hemp, jute and coconut,
their length varying from 1 mm to 550 mm (FIBROUS)
• Func_on
– Gives mechanical support to the plant by giving rigidity, flexibility
and elas_city to the plant body.
88. THE ORGAN SYSTEMS
• Integumentary system
• Muscular system
• Skeletal system
• Nervous System
• Endocrine System
• Circulatory system
• LymphaMc system
• Respiratory system
• DigesMve system
• Urinary and Excretory
System
• ReproducMve System
90. HOMEOSTASIS: internal and external
balance
• Animals cannot survive
unless they are able to
control the internal
environment of their
body, despite con5nual
changes in their
surroundings
91. Controller output (informa_on
CONTROLLER/ modula_ng effector ac_vity)
EFFECTOR
INTEGRATOR
Sensor output (informa_on Effector output (one or more
conveying the current level of the ac_vi_es influencing the level of the
controlled variable controlled variable
Physical system
impacted by
SENSOR effector ac_vi_es
Detec_on and Measurement of (controlled variable)
the controlled variable
disturbances
98. ORGAN SYSTEMS FOR HOMEOSTASIS
• MEMBRANE TRANSPORT SYSTEMS
– OsmoregulaMon and ExcreMon
– regulaMon of water and ion concentraMons in the
body
• criMcal in maintaining life in a cell
– balance of water and ions is partly linked to excreMon
• removal of metabolic wastes from the body
• ORGAN SYSTEMS
– Waste ExcreMon‐Related Systems
– Endocrine System
– Nervous System
102. WHAT IS EXCRETION?
• The removal of cellular waste products from
an organism
• Example of Wastes:
– RespiraMon‐associated wastes: carbon dioxide +
water
– Metabolism‐associated wastes: water (from
dehydraMon synthesis; nitrogenous wastes/urea
(from protein metabolism and those produced
from excess amino acids) and mineral salts
104. LIVER AND LUNGS
LIVER LUNGS
• deaminates amino acids • Excrete carbon dioxide and
• converts ammonia to urea water
(ammonia is very toxic)
105. SKIN/SWEAT GLANDS AND LARGE
INTESTINES
SKIN/SWEAT GLANDS LARGE INTESTINES
• INCIDENTALLY EXCRETORY • expels feces and excess salts
• Aid in temperature regulaMon of
the body
• conserves water
• evaporaMon of the sweat (98%
water and 2% salts and urea)
lowers body temperature
(temperature regulaMon)
• Excretes urine like wastes (water,
salt, and some urea)
107. • excrete most of the
KIDNEYS urea
• control the
concentraMon of most
of the consMtuents of
the body fluids
• filters out wastes and
reabsorbs needed
materials like water,
sugar & protein
108. HUMAN URINARY • Kidney: filters out wastes
and resorbs needed
TRACT materials like water
• Ureter: carries urine from
the pelvis to the urinary
bladder (one from each
kidney)
• Urinary bladder: short
term storage area for the
urine
• Urethra: conducts urine
from the bladder to the
outside of the body
110. HOW IS URINE PRODUCED?
• Filtra_on
– water and dissolved substances
out of the blood
– Glomeruli into Bowman's capsule
• Re‐absorp_on
– water and dissolved substances
out of the kidney tubules back into
the blood
– this process prevents substances
needed by the body from being
lost in the urine
• Secre_on
– hydrogen ions (H+), potassium
ions (K+), ammonia (NH3), and
certain drugs out of the blood into
the kidney tubules
111. • urinalysis is
composed of two
examinations:
– Chemical tests
for abnormal
chemical
constituents
– Microscopic exam
for abnormal
insoluble
constituents
115. NERVOUS VERSUS ENDOCRINE
REGULATION
Characteris_cs Nervous System Endocrine System
MECHANISM OF CONTROL Neurotransmiher released Hormones delivered to
in response to nerve Mssues throughout the
impulses body by the blood
CELLS AFFECTED Muscle cells, gland cells, Virtually ALL body cells
other neurons
TYPE OF ACTION THAT Muscular contracMon or Changes in metabolic
RESULTS glandular secreMon acMviMes
TIME TO ONSET OF ACTION Typically within millisecs Seconds to hours or days
DURATION OF ACTION Generally more brief Generally slower/longer
116. REGULATION VIA THE NERVOUS
SYSTEM
• Communication network
that allows an organism to
interact in appropriate ways
with the environment
– Sensory components
• Detect environmental
events
– Integrative components
• Process sensory data and
information stored in
memory
RECALL:
– Motor components
• Generate movements and HOMEOSTASIS!!!
other activities
119. REGULATION VIA THE BRAIN
• It is the center for
registering sensations,
correlating them with one
another and with stored
information, making
decisions, and taking
action
• It is the center of
intellect, emotions,
behavior, and memory
• It directs our behavior
toward others
120. THE LOBES: FOR YOUR APPRECIATION
• THE CASE OF PHINEAS
GAGE:
• The inch-thick tamping rod
rocketed through his cheek,
obliterating his left eye on its
way through his brain and
out the top of his skull
– Yet a moment later he stood
up and spoke
– Within two months:
completely recovered--he
could walk, speak, and
demonstrate normal
awareness of his
surroundings
• But: the character of the
man did not survive the
tamping rod's journey
through his brain
125. REGULATION VIA THE SPINAL CORD
AND THE REFLEX
• Extension of the brain stem
starting at the foramen and
ending at L1 (humans) or S2
(animals)
• 2 GENERAL ROLES
– Transmission of nerve impulses
– Relays informa_on to and from brain
• Ascending and descending paths in the
spinal cord
– Spinal reflexes
126. REFLEX: THE “BRAINLESS” PATHWAY
• Responses to
changes in the
environment
– Automatic
– Fast
– Predictable
• Help maintain
homeostasis
– Allow rapid response
to changes
– Involve spinal cord and
nerves
127. FOR YOUR APPRECIATION: THE
STRETCH REFLEX
Important in Prevents damage to
maintaining muscle muscles and
tone and muscle tendons as a result
coordination of stretching
128. FOR YOUR APPRECIATION: THE
FLEXOR REFLEX
Defensive removal of a limb
from a threatening or
damaging stimulus
129. FOR YOUR APPRECIATION
PRIMITIVE REFLEX: BABINSKI GAG REFLEX
• present in infants; but as
the nervous system
matures, they are
suppressed or overridden
• Example: Babinski or
plantar reflex
– When the sole of an
infant's foot is stroked, the
toes go upward and may
fan out
– In a normal adult, this
does not happen; instead,
the toes go downward
130. THE PNS AND HOMEOSTASIS
Peripheral
nervous system
Motor
Sensory division
division
Sensing Sensing Autonomic Soma_c
external internal nervous system nervous system
environment environment (involuntary) (voluntary)
Sympathe_c
Parasympathe_c
division
division
131. The vertebrate PNS consists of paired
cranial and spinal nerve and associated
ganglia
• Cranial nerves
– Originate in the brain
and innervate organs of
the head and upper body
– Convey sensory inputs to and
motor outputs from the brain
• Spinal nerves
– Originate in the spinal
cord and innervate the
entire body
• Mammals: 12 pairs of
cranial nerves and 31
pairs of spinal nerves
132. FOR YOUR APPRECIATION: THE
CRANIAL NERVES
Cranial nerve Nerve type (Sensory, Motor, Both)
I Olfactory S Sense of smell “On Old Oklahoma’s Towering
Tops a Fine Vet
II Optic S Vision Gastroenterologist Viewed Some
Horses”
III Oculomotor M eye movements, pupillary constriction and
accommodation, eyelid muscles
“Six Sailors Made Merry But My
IV Trochlear M Eye movements Brother Said Bad Business My
Man”
V Trigeminal B somatic sensations from face, mouth, cornea; muscles of
mastication (chewing)
VI Abducens M Eye movements
VII Facial B controls the muscles of facial expression, taste from
anterior tongue, lacrimal (tears) and salivary glands
VIII Vestibulocochlear S hearing, sense of balance
IX Glossopharyngeal B sensation from pharynx, taste from posterior tongue,
carotid baroceptors
X Vagus B autonomic functions of gut, sensation from pharynx,
muscles of vocal cords, swallowing
XI Spinal Accessory M Shoulder and neck muscles
XII Hypoglossal M Movement of tongue
134. PARASYMPATHETIC DIVISION SYMPATHETIC DIVISION • Sympathetic (active
mode)
Brain Eye
– Correlates with arousal
Constricts
pupil
Dilates
pupil
and energy generation
Salivary
glands – Heart beats faster, liver
S_mulates
saliva Inhibits converts glycogen to
saliva
produc_on
produc_on glucose, bronchi of
lungs dilate and support
Constricts
Lung
Relaxes increased gas exchange
bronchi
bronchi – Inhibits digestion
Slows
Accelerates
heart
– Stimulates secretion of
Heart Adrenal
heart
gland adrenaline from the
S_mulates
adrenal medulla
epinephrine
Liver and norepi‐
Spinal Stomach nephrine release
cord • Parasympathetic
S_mulates
stomach, Pancreas S_mulates
glucose (relaxed mode)
pancreas, release
and intes_nes – Causes the mirror image
Inhibits
Intes_nes stomach, – A calming and a return
pancreas,
and intes_nes emphasis on self-
Bladder
S_mulates Inhibits maintenance functions
urina_on urina_on
– Decreases heart rate
Promotes Promotes ejacu‐
and energy storage
erec_on of
genitals
Genitals la_on and vaginal
contrac_ons – Enhances digestion
135. FOR YOUR APPRECIATION
• LEARNING: A
process by which
behavior is
modified on the
basis of
experience
• MEMORY: storage
of information
that has been
learned
137. CAN HORMONES • Regulate the chemical composition and volume
of the internal environment (extracellular fluid)
CONTROL YOU? • Help regulate metabolism and energy balance
• Help regulate contraction of smooth and
cardiac muscles and secretion by glands
• Help maintain homeostasis despite disruptions
such as infection, trauma, emotional stress,
dehydration, starvation, etc.
• Regulate certain activities of the immune
system
• Play a role in the smooth, sequential
integration of growth and development
• Contribute to the basic processes of
reproduction (gamete formation, fertilization,
nourishment of embryo and fetus, delivery, and
nourishment of newborn
138. TYPES OF HORMONES AND THEIR
MECHANISM
• STEROIDS
– Testosterone (male sex
hormone)
– Estradiol (responsible for
many female sex
characterisMcs)
• NON‐STEROIDS
– PEPTIDES
– AMINES
139. FOR YOUR APPRECIATION
• ESTROGENS OR THYROID • ENDOCRINE‐RELATED
HORMONES DISORDERS
– Steroid hormones; lipid-soluble – OverproducMon of a hormone
– Not split apart during digestion
– Easily cross the intestinal lining
because they are lipid soluble – UnderproducMon of a hormone
• INSULIN – NonfuncMonal receptors that
– Water-soluble peptide and cause target cells to become
protein hormone insensiMve to hormones
– Not effective oral medications
because digestive enzymes
destroy them by breaking their
peptide bonds
– That is why they are taken by
injection
142. FOR YOUR APPRECIATION:
PROLACTIN
• WHY YOUR BREAST IS ENLARGED
AND PAINFUL BEFORE YOUR
PERIOD:
• PIH (dopamine) inhibits
release of PRL from the
anterior pituitary gland
• As the levels of estrogen and
progesterone fall just before
menstruation begins, the
secretion of PIH diminishes
and blood level of PRL
increases
• Breast tenderness just before
menstruation may be caused
by elevated levels of PRL
144. FOR YOUR APPRECIATION:
HORMONES AND YOUR URINE
• STIMULATES ADH (antidiuretic • CAUSES of DI
– Neurogenic DI: Results from
hormone) SECRETION hyposecretion of ADH due to brain
– Pain, Stress, Trauma, Anxiety tumor, head trauma or brain surgery that
may have damaged the posterior pituitary
– Acetylcholine, Nicotine gland and hypothalamic nuclei
– Nephrogenic DI: The kidneys do not
– Drugs (morphine, tranquilizers respond to ADH; ADH receptors may be
and some anesthetics) non-functional or the kidneys may be
damaged
• INHIBITS ADH SECRETION • SYMPTOMS
– Alcohol, Caffeine – Bed wetting
– Exclusion of large volumes of urine
• Increases urine output (dehydration and thirst)
• Dehydration causes both
• TREATMENT
the thirst and typical
– Hormone replacement therapy (ADH
hangover the day after injection or sprays)
– Restriction of salt in the diet and diuretic
drugs
• Diabetes insipidus
– ADH disorder
145. THE THYROID AND PARATHYROID
HORMONES
• Parathormone
– Controls the calcium
ion concentration of
the body by:
ENDEMIC • Absorption of
GOITER calcium from the
CRETINISM EXOPHTHALMOS
gut
• Excretion of
calcium by the
kidneys
• Release of calcium
GOITER IN from the bones
MYXEDEMA EWE
146. HORMONES OF THE ADRENAL
GLANDS
• The adrenal glands produce the hormones
that stimulate the thirst center
• When enough water is provided, the tongue,
the stomach and the intestine send the
message that the reserves are filled
• The hypothalamus orders the saliva glands
to stop production, and the result is a dry
mouth
• Many times in the course of a day we feel
thirsty and so drink a glass of water
– Cells in the various organs of the body
determine the water needs of the body
and work with one another in a series of
operations by which a person is urged
to drink water
147. FOR YOUR APPRECIATION: THE
ADRENALINE RUSH
• Adrenaline is secreted
immediately in the body
of a pilot whose
airplane malfunctions
• This fluid sends more
sugar and blood to the
brain, making the pilot
more attentive
• His blood pressure and
heartbeat increase, heart beats faster = sugar in her blood
increases = added strength in
making him more alert muscles = able to escape the danger
149. FOR YOUR APPRECIATION:
HORMONES FOR CHILD BEARING
• Human chorionic • Progesterone
gonadotropin – Promotes special development
– Promotes growth of the corpus of the uterine endometrium in
luteum and secreMon of advance of implantaMon of the
estrogens and progesterone by ferMlized ovum
the corpus luteum – Promotes development of
some fetal Mssues and organs
• Estrogens – Promote development of the
secretory apparatus of the
– Promote growth of the mother’s breast
mother’s sex organs and of
some of the Mssues of the fetus
• Human somatomammotropin
– Promotes growth of some fetal
Mssues as well as mother’s
breast
150. FOR YOUR APPRECIATION: CAN’T
SLEEP WITH THE LIGHTS ON?
• PINEAL GLAND: SUPRACHIASMATIC SUPERIOR
Consists of nueroglia RETINA
NUCLEUS
(IN
CERVICAL
GANGLION
PINEAL
GLAND
and secretory cells HYPOTHALAMUS) (SYMPATHETIC)
called pinealocytes
IN
• Hormone: melatonin IN THE
LIGHT
DARKNESS
(biogenic amine)
• Timing of the body’s LACK OF
biological clock NOREPINEPRHINE
INHIBITS
NOREPINEPHRINE
STIMULATES
MELATONIN
MELATONIN SECRETION
SECRETION
ALERT! ZZZZ….
151. FOR YOUR APPRECIATION:
MELATONIN AND JET LAGS
• SAD (seasonal affective disorder)
– Type of depression that arises
during winter months when day-
length is short
– Due to overproduction of
melatonin
– Relief: bright light therapy
(exposure to artificial light as
bright sunlight)
• JETLAGS
– Tiredness suffered by travelers
who cross several time zones
– Relief: 3-6 hours of bright light
exposure
• INSOMNIA
– Inadequate production of
melatonin
– Research: small doses of
melatonin before bedtime
