ANFS345 Exam 4

Energy comes from...

mitochondria
comes from carbohydrates, lipids, proteins (requires oxygen to produce energy)

Mitochondria

all cells have mitochondria except red blood cells
different amount of mitochondria dependent on where the cell is
cell that requires more energy -> more mitochondria
cells that require less energy -> less mitochondria

What has the most efficient transfer of outside environment to energy?

Plants (Plants get 0.1% energy from environment)

Energy is used for...

Biosynthesis (food -> energy)
Maintenance (housekeeping, i.e. penguin keeping itself warm)
Generation of external work (what to do with unused energy)

Small Animal Food Consumption

As a percentage of body weight, smaller animals consume more food
smaller animals have higher metabolic rates
has more surface area per unit weight

Large Animal Food Consumption

Bigger animals consume less food than body weight
bigger animals have slower metabolic rates
has less surface area per unit weight

Glycolysis

Number one source of producing energy
glycolysis breaks down glucose (glucose needs to be kept in a certain range)
glucose is breakdown product of almost all carbohydrates
proteins and lipids can be converted into glucose
Glycolysis occurs in the cytosol of the cell
cytosol is the liquid inside the cell
Glycolysis does not require oxygen (anaerobic)

Glycolysis Process

Glucose -> glucose-6-phosphate
phosphate comes from ATP
Fructose-6-phosphate is broken in half into DHAP and GAP
DHAP is not metabolized further, forms more GAP
GAP can produce more ATP
GAP -> 1,3-DiPG
2 1,3-DiPG are produced
1 GAP molecule is used, 1 DHAP molecule is converted to GAP then converted to 1,3-DiPG
1,3-DiPG -> 3-PG
when converted 2 ATP molecules are produced
PP -> Pyruvic produces 2 more ATP molecules
Glycolysis produces a net gain of 2 ATP per glucose molecule

Krebs Cycle/Citric Acid Cycle (CAC)/ Tricarboxylic Acid Cycle (TCA)

If body has access to oxygen, it will take pyruvic acid and bring it through the TCA cycle
TCA cycle only works when there's access to oxygen

TCA Process

has 8 reactions
TCA cycle functions in mitochondria
more mitochondria = more cycles
Pyruvic acid -> acetyl coenzyme A and producing NADH2
acetyl coenzyme A goes through TCA cycle
acetyl coenzyme A interacts with oxaloacetate to form citrate
TCA cycle gives 3 NADH2 molecules, 1 GTP, and 1 FADH2
GTP = ATP
each FADH2 gives ~ 1.5 ATP
each NADH2 gives ~ 2.5 ATP
a total of ~ 10 ATP from 1 TCA cycle

Electron Transport Chain (ETC)

ETC only functions when there is access to oxygen
ETC functions in mitochondria
Inner membrane of mitochondria doesn't follow outer membrane
causes formation of striations which results in more surface area
Inner membrane has 4 protein complexes (+1 other complex)
forms ETC
As electrons move through, protons go to inter-membrane space

ETC Process - Complex 1

takes electrons from NADH2

ETC Process - Complex 2

does not allow proton movement
takes electrons from FADH2
directly transfers electrons to ubiquinone
Both electrons from complex 1 & 2 are transferred to ubiquinone (other complex)
Ubiquinone is responsible for transferring those electrons -> complex 3
If electrons can't be picked up by ubiquinone they are leached (move into yellow space) and turn into reactive oxygen species (not good)

ETC Process - Complex 3

Complex 3 transfer electrons -> cytochrome C -> complex 4

ETC Process - Complex 4

Complex 4 transfers electrons to oxygen (final electron acceptor)

ETC Overall output

Complexes move 10 protons
4 protons required to form ATP
produces ~2.5 ATP

Oxidative Phosphorylation

Protons are pushed out through ATP synthase
produces ATP - oxidative phosphorylation
Body can bypass this process
one way is protons being passed back without production of ATP
another way is through UCP1 which produces heat (very common in animals that hibernate)

Lactic Acid Metabolism when O2 Present

Lactic acid buildup results in loss of muscle movement
lactic acid is produced when no oxygen is present
when oxygen is present lactic acid forms pyruvic acid

Fuel For Work

body starts by using glucose to produce ATP
small amount of glucose brought to muscles
decent amount of fatty acids brought to muscle
eventually muscle glycogen levels are depleted while fatty acids in muscles increase
fatty acids get converted back to glucose

Oxygen Use For Work

oxygen uptake continues at a higher rate due to a deficit created

Reproductive System

all other systems happen because they want to support the reproductive system
reproductive system is the driver for everything else - without it there is not need for the other systems
lots of regulation in the reproductive system

Complexity of Reproduction

-animals want to reproduce to transmit DNA forward
-needs to ensure a right environment to move DNA forward
-want to create an environment egg and sperm can meet for positive event of conception
-needs to ensure once it moves forward it is well taken care of
-offspring needs to be taken care of because there is no point in reproducing if offspring isn't taken care of (DNA won't move forward)

Egg and Sperm Meeting Requirements

-Monitoring environment (what are the environmental cues? Is it a good time for reproduction to happen?)
-Right location
-Right set of organs (organs need to be compatible for reproduction to happen)
-Right resources for event to happen
-Attraction between male and female
-Needs event of spawning or copulation

Successful Offspring Requirements

-Zygote needs to develop (right nutrients)
-Forming offspring (need enough resources to go into offspring)
-Early epigenetic tagging (individuals transmit information to offspring by DNA and epigenetic signals)
-Time each offspring gets
-Environmental stressors offspring experiences
-Offspring needs to evade predators

Components of Reproduction

-Mate association
-Right reproduction cycle
-Organs and cells need to work together
-Provision for offspring (providing resources)
-Distinctive physiology that allows them to evade predators

How sex is determined

X and Y chromosomes determine sex
XX is female XY is male
determined by father since mom can only give X
Genetic sex determinants can be different across animals

Birds and some reptiles sex determination

sex determined by mom because ZZ is male (can only give Z) females have ZW

Some Insects sex determination

a queen that mates and stores sperm from males, stored fertilized eggs are females, sperm that's not fertilized are males (haplodiploid system)
ex. ants

Animals like alligators and turtles sex determination

sex is not determined by genetics, but temperature
(for turtles, warm temps produce females, cool temps produce males)

Some Tropical Fish sex determination

sex is not determined until later in life (all start as males and some become females)

Worms sex determination

sex is determined by where a larva falls on sea floor (if it lands on open sea floor it's a female, if it falls on top of a female it's a male)

Desert Tail Lizard sex determination

mostly all females

Seasonality of Reproduction

Animals are define to a certain area
Animals in tropics tend to breed all year long
Animals in cold regions only breed during certain times of year
doesn't breed when really cold because it's more important to preserve body heat

Silkworm moth seasonality of reproduction

In spring it will lay its first clutch of eggs
eggs will mature into adults that will lay eggs
eggs are programmed to enter diapause
diapause tends to kick in during winter
eggs then hatch when temperature goes back up

Antarctic fur seal seasonality of reproduction

birth happens right at start of summer season (estrus)
mating occurs but with delayed implantation
leads to delay in development of placenta
diapause/delayed implantation lasts through winter until weather gets warm again

Differentiation of external genitalia

When a fetus develops it always requires the same "ingredients"
Organs develop into either male or female genitalia

Development of external genitalia

Initial formation is the same for both
has organs that can develop into either male or female
both have urethral fold and genital tubercle
As they develop, glands continue to develop along with urethral fold
In males penis shaft develops, in female penis shaft is taken away, tubercle is reabsorbed and there's development of urethral fold
development isn't always complete at all times causes differences in development in external genitalia of both males and females
independent of if male is xx or female is xy - determined by genetics

Female Reproductive System

female reproductive system in all mammals is more complicated than male reproductive system
due to storage of follicles that develop into eggs allowing offspring to be developed with contact with sperm

Female Reproductive System Organs

Vagina-outside area
cervix and uterus-uterus is where implantation happens
oviducts and ovaries-where follicles are stored
follicles move through oviducts -> uterus when matured
most mammals have 2 ovaries:
-don't work at the same time
-inside ovaries are sacs with primordial follicles which
are stored and formed when a child is born

Function of Primordial Follicles

start of with hundreds of thousands of primordial follicles
during each cycle some of primordial follicles become primary follicle which becomes secondary follicles
only one secondary follicle develops into a mature follicle
mature follicle moves to uterus looking for successful contact with sperm
ruptured follicle becomes corpus luteum which secretes hormones to influence successful interaction with sperm
if not successful, corpus luteum goes away

Follicular Phase

primordial follicle ->primary -> secondary -> mature -> ovulation
development in this phase is due to FSH which assists in maturation of follicle
right before ovulation there is a peak in LH

Luteal Phase

ovulation -> oocyte released -> corpus luteum

Hormones Involved During Possible Fertilization

when FSH is secreted there's high levels of estrogen released
as soon as ovulation happens estrogen (allows follicle to develop) drops a little and progesterone increases (ensures successful implementation and successful pregnancy)
Inhibin counteracts FSH
When oocyte meets sperm this occurs in uterus
oocyte implants on endometrium and it thickens and blood vessels go through in expectation of successful pregnancy

Menstrual Cycle

If implantation is not successful, progesterone levels decrease and all other tissues flushed out through menstrual cycle
not all animals have a menstrual cycle some go through heat / estrus phase (Monkeys, apes, humans and some elephant shrews are the only mammals with a menstrual cycle)
mammals that have a menstrual cycle can mate/copulate at any time while animals that go through estrus can only mate/copulate when in estrus

Function of menstrual cycle

Placenta connects to mother blood supply and nourishes fetus
confined behind barrier of maternal cells
in humans and other species placenta penetrates right into maternal system to allow permanent blood flow
endometrium only selects for best embryos
to protect body from risks of unsuccessful embryo - sperm interaction by having a menstrual cycle to get rid of all tissues grown in expectation of successful implementation

Mature follicle cells

theca cells (outside), then granulosa cells then zona pellucida (inside)

Hormone control of female reproductive system

GnRH is released from hypothalamus which tells anterior pituitary to release FSH and LH
LH and FSH are carried in blood -> mature oocyte
Theca cells produce androgens
female reproductive system produces androgens which help with process of sexual copulation
androgens are changed to estrogen using aromatase enzyme
Estrogen is secreted into general circulation and along with FSH stimulation of proliferation is increased
Corpus luteum is what produces progesterone

Follicular phase hormones

GnRH
LH
FSH
androgens
estrogen
inhibin

GnRH

stimulates release of FSH and LH

LH

stimulates theca cells to secrete androgens during follicular phase
surge of LH triggers final maturation of the oocyte and ovulation
following ovulation, LH initiates transformation of follicle cells to corpus luteum

FSH

stimulates aromatase action in granulosa cells for conversion to estrogen

Androgens

diffuse from theca cells -> granulosa cells for conversion to estrogen

Estrogen

acting together with FSH, stimulates proliferation of granulosa cells
at low concentrations, has negative feedback effect on anterior pituitary keeping FSH and LH secretions low
at high concentrations, has positive feedback effect on anterior pituitary promoting LH surge
promotes estrous behavior (in species that exhibit estrus)
promotes growth of endometrium and development of endometrial progesterone receptors

Inhibin

inhibits FSH secretion

Luteal phase hormones

progesterone
estrogen
inhibin

Progesterone

causes endometrium to become secretory; promotes relaxation of uterine and oviduct smooth muscles

Estrogen

acting together with progesterone, reduces secretion of FSH and LH from anterior pituitary; thereby greatly suppresses folliculogenesis in primates and slows folliculogenesis in other mammals

Inhibin

inhibits FSH secretion

Pregnancy hormones

chronic gonadotropin
progesterone
estrogen
lactogen

Chronic gonadotropin

secreted by embryonic placental cells in primates and horses, in which it rescues the corpus luteum and ensures the maintained function of the corpus luteum

Progesterone

opposes stimulatory effect of estrogen on uterine smooth muscle until late in pregnancy
stimulates secretion of prolactin from anterior pituitary
acting together with estrogen and prolactin, promotes growth of mammary glands

Estrogen

acting together with progesterone and prolactin, promotes growth and development of mammary glands
acting together with progesterone, prevents milk secretion by mammary glands
prepares uterine smooth muscle for parturition by promoting production of oxytocin receptors and synthesis of connexins that form gap junctions between muscle cells
stimulates enzymatic breakdown of cervical collagen fibers, thereby softening the cervix

Lactogen

alters maternal glucose and fatty acid metabolism to shunt glucose and fatty acid to the fetus; may contribute to development of capacity for lactation

Ovulation in rabbits

Rabbits undergo estrous cycle
As soon as copulation happens there is a drastic LH surge within 1-2 hours of copulation
allows potential pregnancy to sustain

Hormone control of ovulation in rabbits

Copulation stimulates sensory neurons in cervix which goes back to brain and activates GnRH by norepinephrine
GnRH is secreted into hypothalamo-hypophysial portal -> anterior pituitary by blood
GnRH stimulates anterior pituitary to secrete LH
Surge of LH stimulates ovulation in ovaries

Testes

similar to ovaries in female repro system
produce sperm (by seminiferous tubule)
in sac called scrotum

Seminiferous tubules

surrounded by leydig cells
inside contains sertoli cells

Leydig cells

secrete testosterone

Sertoli cells

support primary spermatocyte -> secondary spermatocyte -> spermatids -> mature sperm

Scrotum

typically outside body because testes need to be at lower temp than rest of body for sperm to be active

Vas deferens

similar to oviduct
allows sperm to move

Seminal vesicle and prostate gland

extremely important in providing secretions (seman) giving sperm nutritional environment to survive
prostate gland is most common to develop cancer
similar to clitoris/skins gland in female repro system

Penis

seamen and sperm exit through penis
similar to vagina

Sperm structure

tail - allows it to swim by swirling
mitochondria within midpiece - provides energy to movement
nucleus
acrosome - really important, has enzymes that allow it to break into female ovum (has receptors-need matching receptors in female)

Hormone control in male reproductive system

conception - 1-17 weeks after conception is determination of male or female
somatic sex differentiation
triggered by testosterone in males
falls off until around birth
8 months - a year shows a peak in testosterone
Next peak is at puberty with an increase in sperm production as well

GnRH

stimulates release of FSH and LH from anterior pituitary

LH

stimulates Leydig cells to produce testosterone

FSH

required for development and support of sertoli cells
stimulates sertoli cells to support spermatogenesis in a secondary roll to testosterone

Testosterone

required for mitosis and meiosis of spermatogenesis
stimulates sertoli cells to support and regulate spermatogenesis
exerts negative feedback on anterior pituitary and hypothalamus
mediates secondary sex characteristics such as growth of facial hair and muscular strength
during early development, mediates sexual differentiation of reproductive organs also mediates
sexual differentiation of certain aspects of brain neuroendocrine function and other aspects of brain fine structure and function

Inhibin

inhibits secretion of FSH

Relationship between testes size and mating system in mammals

single-mate vs multi-mate is determined by teste size
animals that have single-mate have smaller testes (produces less sperm)
animals that have multi-mate have larger teste size (produces more sperm)

Fertilization process

lots of sperm around a single ovum (in competition with each other)
only one sperm enters through granulosa and oocyte does not entertain any more sperm
sperm binds to receptor on zona pellucida
then uses enzyme and acrosome to create a path in
once path is created sperm enters across the space
once sperm interacts with membrane it releases its genetic contents into cytoplasm of oocyte

Hormone control of fertilization

as soon as there is fertilization there is an increase in estrogen, progesterone and hCG
hCG is secreted instantly after successful fertilization which sustains corpus luteum to keep producing estrogen and progesterone
estrogen and progesterone levels continue to increase during pregnancy, then at birth they drop drastically (can lead to postpartum depression)
oxytocin helps to decrease chance of postpartum depression

Hormone control during parturition

When animal is ready to push out offspring (contractions begin) the hypothalamus is triggered and allows release of oxytocin from posterior pituitary
oxytocin travels through blood (increasing levels) and stimulates muscles to contract
prostaglandins allow contractions in a finite way and increasing muscle stimulation to allow enough strength to push out offspring

Placental mammals process of birth

includes humans, dogs, cats, giraffes and blue whale
placenta attaches to wall of uterus to support fetus
funnels nutrients and oxygen through umbilical cord
fetus spends more time in animal

Marsupials process of birth

includes quoll, kangaroo
tiny and delicate when born
must continue development in mother's pouch

Monotremes process of birth

includes 4 types of echidnas and platypus
same orifice for reproduction, excretion and egg laying
lay soft shell eggs

Energy consumption during reproduction

energy consumption increases once there is an established pregnancy
continues to increase even after offspring is born while lactation is occurring
energy only drops off when animal starts weaning process

Mammary gland composition

veins and arteries -requires good blood supply so nutrients can travel through and get to offspring
alveoli - where milk is produced
milk ducts - where milk is collected
cisterns - cavity where milk can collect between two milkings
teat - where milk is excreted

Hormones involved in mammary gland and lactation

As offspring is suckling muscles around teat are activated telling brain it needs to support process of milk production
activates anterior pituitary gland reducing dopamine and increasing TRH (Thyrotropin-releasing hormone) which results in secretion of prolactin and oxytocin
prolactin stimulates alveolar epithelial cells to produce milk (milk stays here)
oxytocin allows for the milk to be excreted to offspring

Sensory transduction

sensory stimulus needs to be changed to an electrical signal
2 main methods-
1. Ionotropic transduction
2. Metabotropic transduction

Ionotropic transduction

depends on certain ions
more direct - as soon as stimuli interact with receptors, the receptors open up

Metabotropic transduction

depends on metabolic compounds
less direct - stimuli interact with receptor (g-protein receptor) which initiates a secondary cascade that activates the channel
allows for more regulation

Receptors that use ionotropic transduction

mechanoreceptors
vestibular receptors
osmoreceptors
auditory receptors
thermoreceptors
electroreceptors
some taste chemoreceptors (salty and sour)
olfactory chemoreceptors in insects

Receptors that use metabotropic transduction

some taste chemoreceptors (sweet, bitter, umami)
photoreceptors
olfactory chemoreceptors in vertebrates

Principle of labelled lines

peripheral nervous system picks up stimuli and communicated with central nervous system via neurons using action potential
taste, light and sound - sensory receptors interact with another neuron that then brings info to central nervous system (more regulation)
touch and smell - sensory receptor directly synapse with central nervous system (less regulation)
sense stimuli end up at different parts of the brain
this principle determines what the sense is based on where the line in the brain is

Insect mechanosensory mechanism

Each sense picks up 2 things
intensity of stimuli (hard vs. soft)
length of stimuli (in time)

Small amount of hair movement

low intensity
ex. light breeze

Medium amount of hair movement

more intensity
action potential is being used
ex. strong wind

Strong amount of hair movement

extreme intensity
a lot of action potential
ex. severe windstorm