Exam 4 Flashcards
1
Q
Features of animals that live in warm climates
A
Long limbs and long skinny bodies
- In camels, thick knee pads to protect from heat
2
Q
Features of animals that live in cold climates
A
Thick layer of blubber, rounder shape, higher cholesterol
3
Q
Q10
A
Temperature quotient - measure of the thermal sensitivity of a chemical reaction or physiological process. Increase in a rate caused by a 10˚C increase in temperature
4
Q
When will heat transfer be positive
A
If external temp is greater than internal temp (gain heat)
5
Q
When will heat transfer be negative
A
If external temp is less than internal temp (lose heat)
6
Q
Equation for heat balance
A
Body heat = Heat produced + (heat gained-heat lost)
7
Q
Conduction
A
Direct transfer of thermal energy of molecular motion; takes place between physical bodies that are in contact with each other (ex. heat loss from body sitting on a cold rock)
8
Q
What is the rate of transfer of thermal energy dependent on
A
thermal conductivity (lamda)
temperature gradient ∆T
distance L
9
Q
Resistance
A
1/conductance; insulation is a measure of resistance
the higher the insulation the lower the conductance
10
Q
What is conductivity influenced by
A
the medium it travels through (conductance of water greater than air)
11
Q
Animal insulation
A
Hair, feathers, fur, and subcutaneous fat (blubber in aquatic animals)
Seasonal changes in thickness as well
12
Q
What does fourier’s law state
A
As fur thickness increases, insulation increases
13
Q
Convection
A
Mass movement of the gas or fluid contributes to renewal of the fluid at the boundary; accelerates heat transfer
14
Q
Radiation
A
Heat transfer takes place in the absence of direct contact; due to emission of electromagnetic radiation (ex holding hands up to fire)
15
Q
Evaporation
A
Removes heat from the body (ex. sweating), always negative
16
Q
SA:V ratio in small vs large animals
A
Large animals have a very low SA:V ratio and tend to live in colder climates
Small animals have a very high SA:V ratio and live in warmer climates
17
Q
What is an example of a behavioral mechanism to gain/lose heat?
A
Baby penguins huddling together to reduce the exposed surface area
Migration of birds to avoid unfavorable conditions
18
Q
Poikilotherm
A
changes temperate season to season or day by day
19
Q
Homeotherms
A
have stable body temperature
20
Q
Ectotherms
A
- environment determines body temperature (heat comes from outside)
- lower metabolic rate as they do not produce enough heat metabolically to keep themselves warm
- includes all invertebrates, fishes, amphibians and reptiles
- do not occur in the earth’s coldest environments
21
Q
Endotherms
A
- Animals generate internal heat to maintain body temperature (heat comes from within)
- higher metabolic rate
- includes birds and mammals
physiological thermoregulation by producing heat through metabolic means
22
Q
Thermoneutral zone (TNZ)
A
Range of temperatures optimal for physiological processes; metabolic rate is minimal
23
Q
Upper critical temperature (UCT)
A
Metabolic rate increases as animal induces a physiological response to prevent overheating
24
Q
Lower critical temperature (LCT)
A
Metabolic rate increases to increase heat production
25
Temporal heterotherms
Change temperature over a period of time (hibernating animals, pythons after a large meal)
26
Regional heterotherms
Body temperature varies in regions of the body (billfish with heater organs in eyes, tuna retain heat in red muscle, great white sharks with countercurrent exchanger)
27
Behavioral mechanism importance
Changing body location or position to change or minimize body temp, most important in ectotherms
28
Homeoviscous adaptation
Ectodermal animals reduce the deleterious effects by changing the cell membrane composition
- fatty acid chain length
- saturation
- phospholipid classes
- cholesterol content
29
Cold climate animal membrane fluidity
low fluidity, shorter chains of fatty acids,
more unsaturated fatty acids, an increased PC:PE ratio, and less cholesterol
30
Warm climate animal membrane fluidity
high fluidity, longer chained fatty acids, more saturated fatty acids, more PE, and more cholesterol
31
In situ modification
1. phospholipase cleaves a fatty acid chain off of a phospholipid and results in a lysophospholipid
2. Acyl CoA synthesis make another fatty acid into fatty acyl CoA
3. lysophospholipid acyltransferase adds a fatty acyl CoA to the lysophospholipid
32
De novo modification
When temperature decreases, the cell produces vesicles possessing phospholipids with fatty acids that are shorter and more unsaturated than those in the cell membrane.
Over time, cycles of endocytosis and exocytosis remove undesirable phospholipids, replacing them with more desirable ones
33
Seal milk vs human milk
seal milk has lower water and higher fat content
34
Heat Shock Response
1. Heat stress causes complex of HSF and Hsp's to dissociate
2. Hsp 70 binds to denatured proteins
3. HSF monomers associate into trimers
4. Trimers move into the nucleus and bind to the promoter of genes with heat shock element (HSE)
5. Hsp70 gene transcription increases
6. Poly A+ mRNA is exported to the cytoplasm and translated to form more Hsp70
7. The increase in Hsp70 levels allows the complex to form again, stopping transcriptional activation
35
Metabolic compensation
Changes in metabolic machinery that allow some ectotherms to maintain optimal metabolic rates at very different ambient temperatures
36
Isozymes
enzymes with same catalytic function work optimally at different temperature
37
What is the purpose of physiological mechanisms
Allow ectotherms to control the rate of change in body temperature
38
Color change
By changing skin color can alter body reflectance - can increase or decrease heat absorption
39
Countercurrent Heat Exchanger
Large fish use the rete mirable to increase the core body temperature
red and blue muscles run countercurrent to one another and warm blood can transfer heat to cold blood. this allows cold blood coming back from the further extremities and warm blood coming from the core to interact with each other and for the warm blood to transfer heat to the cold through conduction
40
Freeze tolerance
some animals allow their tissues to freeze using non colligative properties
41
Cryoprotectant
increase in intracellular solutes concentration decreases the freezing point of water
42
Antifreeze macromolecules
Production of proteins and glycoproteins that decrease the freezing point by noncolligative actions. They disrupt ice crystal formation by binding to small ice crystal and preventing growth
43
Hibernation
a state of regulated hypothermia, lasting several days or weeks that allows animals to conserve energy during the winter
44
2 forms of hibernation
Obligate- have to hibernate regardless of temperature
Facultative - not obligated, depends on temperature and food supply
45
Estivation
A state of dormancy similar to hibernation. Animals that estivate spend a summer inactive and insulated against heat, to avoid the potentially harmful effects of the season. Some animals may estivate to conserve energy when their food and water supply is low
46
Brown Adipose Tissue (BAT)
Important in small mammals, rich in mitochondria and has a good supply of blood.
Unique as it has expression of thermogenin (UCP1)
47
Non-shivering thermogenesis
Required for newborns BAT located around core organs as they can't shiver
Norepinephrine stimulates BAT hyperplasia and hypertrophy
48
How are BAT cells made
Precursor cells are induced to proliferate and then differentiated into BAT cells; triglyceride is synthesized and mitochondria # increases
49
How does thermogenin work
It activates UCP (uncoupling proteins), uncoupling the activity of ETC from ATP synthase so that the energy of oxidation (oxidative phosphorylation) is dissipated as heat rather than used for ATP synthesis.
High rate of fatty acid oxidation
50
Futile cycles and thermogenesis
- Myofibrillar ATPase is recruited during shivering thermogenesis
- Plasma membrane ion (Na+) leaking and pumping
- Nonspecific mitochondrial proton leakage and pumping
- Thermogenin-mediated proton leakage and pumping
- Futile cycling in glcolysis
During nonshivering thermogenesis
51
Shivering thermogenesis
- Unique to birds and mammals
- Uncoordinated myofibril contraction that results in heat production but no gross muscle contraction
- Works for short period of time, muscles are rapidly depleted of nutrients and become exhausted
52
Sweating
- Modified lacrimal glands that release salt water via evaporation which cools down the body
- NaCl in sweat raises heat of vaporization which results in greater heat loss than evaporation of pure water
- Sweating is controlled by the hypothalamus
- To minimize ionic and osmotic problems, the amount of NaCl in sweat decreases during long periods of heat exposure
53
Panting
mucus membrane in esophagus and trachea evaporate
54
Saliva spreading
Many rodents spread saliva on limbs, tails, and on body surfaces to increase heat loss by evaporation
55
Vasodilation
Dilation of peripheral blood vessels to lose heat by increased rate of convection
56
Skin vasculature and heat loss
When temperatures are cold, blood is diverted from the skin through arteriovenous shunts which reduces heat loss
When temperatures are warm, shunts are constricted and blood moves through the vessels closer to the skin surface, enhancing heat loss
57
What is the "thermostat" in the human
The hypothalamus
58
Enzymatic reactions in animals must be done in what kind of environment
An aqueous one
59
Isosmotic solution
Solute concentration inside cell is equal to that outside of cell
60
Hyperosmotic solution
Solute concentration outside cell is greater than solute concentration inside the cell, therefore, water rushes out
61
Hyposmotic solution
Solute concentration inside cell is greater than solute concentration outside the cell, therfore, water rushes into the cell
62
How do animals in marine environments deal with ionic and osmotic change
They tend to gain salts and lose water
63
How do animals in freshwater environments deal with ionic and osmotic change
They gain water and lose salts
64
How do animals in terrestrial environments deal with ionic and osmotic change
They lose water
65
Osmoconformers
Change their bodies osmolarity similar to their environment
- many invertebrates
66
Osmoregulators
Osmolarity is constant regardless of the environment
- most vertebrates (control internal environment)
67
Ionoconformers
Exert little control over ion profile with the extracellular space
- many invertebrates
68
Ionoregulators
Control ion profile within their extracellular space
- most vertebrates
69
Stenohaline
Can only tolerate a very narrow range of salinity
70
Euryhaline
Can tolerate a wide range of salinity
71
Four features of epithelial cells
1. Asymmetrical distribution of membrane transporters
- solutes selectively transported across membrane
2. Cells interconnected to form impermeable sheet of tissue
- little leakage between cells
3. High cell diversity within tissue (especially in kidneys)
4. Abundant mitochondria
- large energy (ATP) supply
72
Transcellular movement
From apical membrane to basolateral membrane or reverse via tight junctions
73
Paracellular movement
Movement between cells via leaky epithelia
74
Movement of Na+/K+ ATPase transporter
Can be with or against the gradient
75
Ion channel movement
Not energy dependent, move with concentration gradient
76
Electroneutral cotransporters
Transfer ions of opposite charges to flow in the same direction
77
Electroneutral exchangers
Transfer ions of opposite charge to flow in opposite directions
78
Osmoregulation in a saltwater fish
Osmolarity of environment greater than internal osmolarity, excretion of salt ions and small amounts of water in concentrated urine from kidneys
79
Osmoregulation in a fresh water fish
Internal osmolarity greater than osmolarity of environment, excretion of large amounts of water in DILUTE urine from kidneys
80
How do animals reduce water flux
They cover their external surfaces with layers of hydrophobic materials
81
Examples of hydrophobic molecules
Mucus
Cornified stratum corneum with keratin (hardened layer)
Cuticle with chitin
all prevent water loss
82
Dietary water
water pre-formed in plant and animal tissue
83
Metabolic water
water is generated as a final step in oxidative phosphorylation
84
Nitrogen excretion
Ammonia produced during amino acid breakdown is toxic and must be excreted
85
What are the three forms ammonia nitrogen is excreted in
Ammonia (ammonioteles)
Uric acid (uricoteles)
Urea (ureoteles)
86
What kind of animals excrete ammonia
Aquatic animals, simple invertebrates, mollusks, worms
87
What kind of animal excretes uric acid
Terrestrial animals including reptiles and birds
88
What kind of animal excretes urea
All mammals, some larval fish
89
Advantages of ammonia excretion
Ammonia is released by deamination of amino acids and requires little energy to produce (only 1 ATP)
90
Disadvantages of ammonia excretion
Highly toxic, requires large volumes of water to store and excrete
91
Advantages of uric acid excretion
Few toxic effects can be excreted in small volumes of water
92
Disadvantage of uric acid excretion
Expensive to produce (many enzymes and NTPs)
93
Advantages of urea excretion
Only slightly toxic, relatively inexpensive to produce
94
Disadvantages of urea excretion
Urea is a perturbing solute (can alter the physical properties of a solution)
95
6 roles of kidneys in vertebrate homeostasis
1. Ion balance
2. Osmotic balance
3. Blood pressure
4. pH balance
5. Excretion of metabolic wastes and toxins
6. Hormone production
96
Function and composition of the nephron
The functional unit of the kidney
Filtration, reabsorption, secretion, excretion
Composed of the renal tubule, glomerulus, and capillary beds surrounding renal tubule
97
Renal tubule
Lined with transport epithelium
Various segments with specific transport functions
98
Glomerulus
Ball of capillaries, surrounded by bowman's capsule
99
Filtration
Filtrate of blood formed at bowman's capsule in the glomerulus (excess molecules and water, primary urine) and flows to proximal tubule
100
Reabsorption
Specific molecules in the removed (water, amino acids, salts in the loop of Henle
101
Secretion
Specific molecules added to the filtrate at the end of the proximal tubule before the loop of henle
102
Excretion
Urine is excreted from the body in the collecting duct
103
What is filtration controlled by
the pressure across the glomerular wall
104
Podocytes
"foot cells" in the bowman capsule with fat molecules and act as a physical filter
105
Glomerular capillaries
Located in the bowman's capsule and allow water and small solutes in
106
Mesangial cells
control blood pressure and filtration within glomerulus
107
Hydrostatic pressure
Blood pressure pushing to make urine
108
Osmotic pressure
backwards pressure that is basically osmosis
109
Force to make urine=
Hydrostatic pressure-oncotic pressure + luminal pressure
110
If you're well hydrated
Hydrostatic pressure > oncotic + luminal pressure
111
If you're dehydrated
Hydrostatic is = oncotic + luminal pressure
112
Glomerular Filtration Rate (GFR)
- determined by pressure acoss glomerular wall
- determined by three main forces
113
Glomerular capillary hydrostatic pressure
Blood pressure, how high bp is going into the afferent arterial
114
Bowman's capsule hydrostatic pressure
Urine pressure going back
115
Osmotic pressure
Osmosis pressure back, the concentration of solutes in the blood that don't pass the membrane. Due to the pressure backward of osmosis
116
Mesangial control
Altered permeability of the glomerulus
117
Myogenic regulation
Constriction/dilation of afferent arteriole
118
Tubuloglomerular feedback
Baro sensor that recognizes urine pressure which causes constriction or dilation of blood vessels
119
Macula Densa
Cells in the distal tubule that control the diameter of the afferent arteriole by sending signals to JG cells
120
juxtaglomerular cells
in afferent arteriole if pressure high, they will cause constriction. If pressure is low, they will dilate
121
Proximal tubule
Most of the solute and water reabsorption
122
Descending loop of Henle
Reabsorption of water, volume of primary urine decreases, primary urine becomes more concentrated
123
The ascending loop of Henle
Reabsorption of solutes, impermeable to water, primary urine become dilute
124
What molecules are secreted during filtration
K+, NH4+, H+, pharamaceuticals, and water-soluble vitamins
125
Where do reabsorbed ions accumulate?
In the interstitial fluid, an osmotic gradient created in the medulla
126
Distal tubule
Can reabsorb salts and water
Can secrete potassium
Transport function of distal tubule affected by hormones
127
Role of parathyroid hormone in reabsorption
Increases Ca2+ reabsoprtion
128
Role of aldosterone in reabsorption
Increases K+ secretion
129
After urine is produced, where does it go?
Leaves the kidney and enters the urinary bladder via ureters, urine is temporarily stored
130
How does urine leave the bladder?
Leaves via urethra
Sphincters of smooth muscle control the flow of urine out of the bladder, opening, and closing of sphincters are controlled by a spinal cord reflex arc (micturition reflex) and can be influenced by voluntary controls
131
How is glucose reabsorbed
Secondary active transport via sodium glucose transporters
132
What does urine concentration depend on
Depends on the permeability (aquaporins) of the collecting duct, which can be regulated by vasopressin (AVP)
133
Diuretics
Stimulate excretion of water
134
Antidiuretics
reduce excretion of water
135
Vasopressin
Made in hypothalamus, peptide hormone, rapid response
136
Aldosterone
made in the hypothalamus, rapid response
137
How does vasopressin work
1. Vasopressin binds G-protein-linked receptor
2. Receptor activates adenylate cyclase, increasing cAMP and activated pkA
3. Phosphorylation of cytoskeletal and vesicle proteins occurs
4. Phosphorylation of cytoskeletal and vesicle proteins occurs
138
How does aldosterone stimulate Na+ reabsorption
1. Aldosterone enters the cell via diffusion
2. Binds to its receptors, a transcription factor
3. Activated transcription factor stimulates transcription of genes for transporters
4. New transporter proteins are made in the ER and exported in vesicles
5. vesicles containing proteins are sent to the plasma membrane
139
How does the renin-angiotensin-aldosterone pathway work (RAA)
When there is low blood pressure, baroreceptors in JG cells release renin -> this coverts angiotensinogen to angiotensin 1 -> angiotensin-converting enzyme (ACE) converts angiotensin 1 to angiotensin 2 -> angiotensin 2 causes synthesis and release of aldosterone from adrenal cortex
140
How does the RAA pathway help to regulate blood pressure
Angiotensin 2 is a vasoconstrictor which raises blood pressure by increasing resistance
Aldosterone increases Na+ and water reabsorption which raises blood pressure by increasing blood volume
141
Asexual reproduction
Progeny are genetically identical (or very similar) to their parent
142
Parthenogenesis
Asexual reproduction in which an egg develops without fertilization
- two females will stimulate copulation with one another which induces oogenesis
143
Budding
offspring grow off parent organism
144
Fragmentation
Pieces breaking off and forming new organism
145
Sexual reproduction
Reproduction of progeny from two parents that contribute nearly equal amounts of genetic material
146
Why choose sexual reproduction
Haploid gametes from a diploid parent
Recombination creates hybrid chromosomes
Diploid offspring offering unique genetic combinations
Creates a population of distinct genotypes
147
Hermaphrodites
Capacity to produce egg and sperm
(Both are male and female, produce male and female gametes)
148
Simultaneous hermaphrodites
Produce egg and sperm at the same time
149
Serial hermaphrodites
Change sex in response to environmental clues
150
Protogynous
Females become males
151
Protandrous
Males become females
152
Overview of sexual reproduction
Fertilization -> cell division -> gastrulation -> morphogenesis -> metamorphosis (not in mammals) -> reproductive development -> senescence and death
153
Determination of sex by genotype in mammals
Y chromosome, homogametic females (XX), heterogametic males (XY)
154
Determination of sex by genotype in birds and butterflies
Heterogametic female (ZW)
Homogametic male (ZZ)
155
Determination of sex by genotype in honeybee (and some ants)
Fertilized = diploid female
Unfertilized = haploid males
156
Temperature-dependent sex determination (TSD)
The temp of egg incubation determines sex, which may be due to hormone levels in the egg
- eggs on the outside of the pile become females, inside become males
157
Oogenesis
Oogonium -> primary oocyte -> secondary oocyte and first polar body -> mature ovum and second polar body
158
Spermatogenesis
Spermatogonium -> primary spermatocyte -> secondary spermatocytes -> spermatids -> mature sperm
159
Ovipary
- ova laid and all development occurs externally
- fertilization can be external or internal
- fish, reptiles, birds
160
Vivipary
- young develop within the female body
- fertilization internal
- mammals and a few other taxa
161
Ovo-vivipary
- ova laid within the mother's body
- develops and hatches internally until birth
- some reptiles and fish
162
GnRH
Gonadotropin-releasing hormone
Synthesized and released from hypothalamus
Delivered to ant pit
Regulates FSH and LH release
163
Gonadotropins
Peptide hormones from ant pit
control steroid hormone synthesis in vertebrates
Includes: LH, FSH, hCG, only in primates
164
Steroid hormones
derived from cholesterol
regulation via gene expression
bind to a nuclear hormone receptor in target
produced in gonads
165
Androgens
Originated in testes, responsible for secondary sex characteristics (axillary hair growth, voice deepening, and libido)
166
LH
Originated in hypothalamus, responsible for leydig cells (stimulates androgen synthesis and release)
167
FSH
Originated in the anterior pituitary, responsible for Sertoli cells (stimulates spermatogenesis)
168
Prostaglandins
Originated in seminal vesicles, responsible for the uterus of mate (induce changes within the uterus that affect sperm motility)
169
What hormone do all reproductive steroid hormones start out at
Progesterone
170
External fertilization
- most common in aquatic animals
- huge gametes numbers are released
- egg release and sperm release are synchronized
- more cells=more chance for successful fertilization
171
Internal fertilization
- Most common in terrestrial animals
- avoid gamete desiccation
- provide protection for embryos
- usually associated with mating behavior and accessory sex organs
172
Copulation
permits sperm to move directly from male reproductive system to female
173
Estrous cycle
- sexual receptivity coincides with a specific phase of the cycle
- amount of uterine tissue lost is minimal to moderate
- present in most mammals except some primates
- when fertile females exhibit behavioral cues and pheromones - called "estrus" or "in heat"
- usually females are only receptive to copulation during heat
174
Menstrual cycle
- sexual reproductivity occurs at many phases of the cycle
- amount of uterine tissue lost is substantial
- present only in some primates (w/a few other exceptions)
175
What are the 3 phases of the menstrual cycle
1. Follicular phase
2. ovulation
3. luteal phase
176
Follicular phase
One follicle grows and matures, estrogen initially drops and then increases tremendously, FSH and LH are pretty even and then dramatically increase after estrogen increases
177
Ovulation
Follicle ruptures, caused by peak of estrogen and FSH + LH, corpus luteum sent to oviduct (around day 14),
178
Luteal phase
Corpus luteum increases in size, progesterone increases for the lining of the uterus, LH and FSH decrease
179
hCG
Analogue of progesterone that is produced by the placenta to maintain uterine lining
180
Steps from ovulation to implantation
1. Ovulation
2. Fertilization
3. Cleavage
4. Cleavage continues down fallopian tubes
5. Blastocyst implants in endometrium
181
Placenta
The interface between mother and fetus
Composed of cells derived from both
182
Trophoblast
Outermost cells of blastula differentiate
183
How does the placenta form
Trophoblast invades the endometrium
184
Function of the placenta in the first trimester of pregnancy
Vital endocrine function
Chorion secretes hCG that causes the corpus luteum to continue to secrete estrogen and progesterone
185
Function of the placenta later in pregnancy
The placenta produces estrogen and progesterone
186
What is parturition in mammals induced by
Contraction of smooth muscle of the uterus
187
Hormonal changes associated with birth
Progesterone levels decrease allowing the uterine muscle to contract
Prostaglandins and oxytocin induce uterine contractions
Placenta expelled soon after birth
188
What produces oxytocin that causes the placenta to release prostaglandins
Fetal cells
189
What releases oxytocin
HPA
190
Prolactin
Peptide hormone released from ant pit that controls milk production
Increases mammary gland mass and ensures biosynthetic machinery in place
Released due to increased estrogen levels during pregnancy
191
How is milk production supressed during pregnancy
High levels of progesterone and estrogen
192
How does oxytocin work to produce milk
oxytocin -> smooth muscles surrounding the gland ducts: contraction -> milk secretion
193
Where are oxytocin receptors located
Glandular and myoepithelial cells of the duct
194
Glandular cells are used for
Milk synthesis
195
Myoepithelial cells
Surround clusters of milk-producing cells
196
G cells
enteroendocrine cells in the stomach that make gastrin
197
Gastrin
targets parietal cells in the stomach to make hydrochloric acid
198
ECF cells
Release histamine that targets parietal cells that make stomach acid
199
What do chief cells do
Make pepsinogen to break down proteins
200
Secretin
Targets liver to make bile and targets pancreas to secrete bicarbonate
201
Vasoactive intestinal peptide
Targets the pancreas to secrete bicarbonate
202
Cholecystokinin
Targets the gallbladder to make bile and targets the pancreas to make enzymes
203
What enzymes does the pancreas secrete
Pancreatic amylase, pancreatic lipase, procarboxypeptidase, trypsinogen, and chymotripsinogen that will be released into the small intestine
204
What do lipases break down
Fats
205
What do amylases break down
Carbohydrates
206
What do proteases break down
Proteins
207
Grehlin
Stimulates NPYRH in hypothalamus -> NPY
Stimulates hunger
Increases gastric motility and acid secretion
208
When are Grehlin levels highest
Before meals
209
When are Grehlin levels highest
After meals
210
How are grehlin levels associated with weight
Negatively
211
What is PPY
secreted from the colon when you are full
suppressed appetite
increased from dietary fiber and breakdown of proteins
212
Leptin
Secreted by white adipose when lipid content is high and suppresses appetite
213
Neuropeptide Y
Produced in arcuate nucleus of the hypothalamus
increases appetite and energy stored as fat
co-expressed with agouti-related protein (AgRP)
214
Pro-opiomelanocortin
Pro-hormones for three hormones
Increases satiety
POMC deficiency leads to insatiable hunger and obesity
215
What happens to white adipose when people are over eating
It gets larger and larger and signals leptin to suppress appetite to POMC to say "I'm full"
216
Starvation
Reorganization of metabolism to survive
217
What happens to glucose during starvation
Conserve glucose to protect glucose-dependent tissues
218
What do muscles shift to during starvation
Lipid metabolism
219
What follows lipid/glucose depletion
Protein metabolism and amino acids are converted to FFA and glucose
220
What happens in later starvation
Glucose and glycogen are depleted, amino acids will start to get used and converted into ketone bodies
221
Hyperphagy
Overeating is essential for some animals in preparation for winter
222
Preproglucagon
Released by the alpha cells of the pancreas and L-cells of the small intestine in the presence of nutrients
223
Proglucagon
gets split into PCSK1 and PCSK2
224
GLP-1
Blocks effects of Grehlin at the hypothalamus which makes you not hungry
225
What does GLP-1 do?
Decrease food/water intake, decrease inflammation, increase secretion of insulin, decrease glucagon synthesis
226
1st law of thermodynamics
Energy cannot be created or destroyed
227
2nd law of thermodynamics
Disorder within an isolated system always increases without the input of energy
228
What is indigestible energy
Feces
229
What is unmetabolizable energy
Urine
230
Function of proteins in the human body
Structural, enzymatic, antibodies, hormones, membrane components
231
Function of carbohydrates in the body
main kCal source/structural/membrane components/kCal storage
232
Function of lipids in the body
kCal source/hormones/cell membranes
233
Vitamins
Organic molecules that function as co-enzymes and other important metabolic functions
234
Minerals
Inorganic compounds/elements with many important functions in metabolism
235
Water
The most abundant inorganic molecule that is necessary to control pH, BP, enzymatic reactions, etc.
236
Where does non-essential AA come from
Biosynthesis from TCA cycle intermediates
237
What are fatty acids derived from
Acetyl-CoA
238
Omega-3 fatty acid
Alpha-linoleic acid (ALA), 3 double bonds, flax seed oil, fatty fish, chia, walnut
239
Omega-6 fatty acid
Linoleic acid (LA), 2 double bonds, vegetable oils, nuts, seeds
240
Vitamin A
Solubility: Fat-soluble
Function: Vission, immunity, reproduction, growth
Deficiency: Blindness, infections, stunted growth
Toxicity: Bone fractures, liver damage
241
Vitamin D
Solubility: Fat-soluble
Function: bone growth, Ca absorption
Deficiency: Rickets, osteomalaciacia
Toxicity: Calcium imbalance
242
Vitamin E
Solubility: Fat-soluble
Function: Antioxidant, cell membranes
Deficiency: Red blood cell breakage
Toxicity: Interferes with medicine
243
Vitamin K
Solubility: Fat-soluble
Function: blood clotting, blood
Deficiency: Clotting
244
Vitamin B
Solubility: water
function: energy metabolism (coenzymes in different processes)
245
Vitamin C
solubility: water
function: antioxidant, collagen formation
deficiency: scurvy
toxicity: diarrhea
246
The mouth
Mechanical digestion
- Chewing
- Pushing of food against the rough hard palate
- Movement/squeezing motion of esophagus
Saliva
- lubricates food, breaks down statch
- parasympathetic (stimulates salvation)
- sympathetic (inhibits salvation)
247
The stomach
HCl acid and protease to break down proteins. Sphincters at the top and bottom. Ridges of muscles on the inside called ruggae for mechanical digestion
248
Small intestine
Most important site of digestion
Very long
digestion and absorption
249
Where does most digestion occur
In the duodenum
250
Villi
increase surface area for digestion
251
Tight junctions
Prevent leakage across epithelium
252
Mucous neck cells
secrete mucus
253
Parietal cells
Secrete HCl in the stomach
254
Function of bile
Aid in the uptake of lipids and emulsify fats, produced in the liver and stored in the gallbladder
255
Gastric inhibitory peptide (GIP)
Decreases in gastric emptying produced by the K cells also stimulated insulin release
256
Enterocytes
Site of absorption in the small intestine
257
Goblet cells
secretes mucus to protect gut
258
Paneth cells
Secrete antimicrobial molecules
259
Where is bile released into
The small intestine
260
What does Glut - 5 Work on
Fructose
261
What does Glut-2 work on
Glucose
262
How are lipids digested
1. DIgestion produced chylomicrons that are taken up by blood and sent to peripheral tissues
2. Chlyomicron remnant is taken up by liver
3. Liver repackages lipid to produce VLDL
4. Triglyceride is depleted from VLDL leaving IDL
5. IDL exchanged material with HDL
6. Liver removed IDL from circulation
7. Liver removes LDL from circulation
8. HDL precursors are produced by liver and intestine
9. HDL is produced
10. HDL provide proteins to IDL
263
Do fats have a higher or lower density than proteins
lower
264
High-density lipoproteins
Good cholesterol
265
Purpose of the large intestine
Absorb water and ions, store and move on insoluble starches and undigested food, site of most of the gut microbiome
