Final exam study guide (new mat) Flashcards
(95 cards)
1
Q
How does the stomach not digest itself?
A
The alkaline mucosal lining protects epithelium from acidity.
2
Q
What is chyme?
A
Food particles + gastric secretions
3
Q
How is the stomach able to size select what passes to the small intestines?
A
Stomach to pylor sphincter (size selection) to small intestine (duodenum)
4
Q
What does the small intestine do?
A
It receives chyme (food particles and gastric secretions) from the stomach. Secretions from the pancreas, liver, and gall bladder.
5
Q
How is the absorption of fats different from other molecules?
A
Fats are water-insoluble, meaning they cannot be directly absorbed into the bloodstream like other nutrients. (from the internet)
6
Q
Why is the production of bicarbonate so important?
A
Bicarbonate ions (HCO3) increase the pH of the highly acidic gastric juices arriving from the stomach (the pH inside the stomach is about 2.0)
7
Q
What else does the pancreas secrete to aid in digestion?
A
HCO3- (bicarbonate): neutralizes acid in chyme
Proteases: trypsin, chymotrypsin, elastase, carboxypeptidase
Fat digestion: lipase, lysopholipase, cholesterol esterase
Nucleic acid digestion: ribonuclease and deoxyribonuclease
8
Q
What is a pancreatic acinus?
A
Secretes digestive enzymes as an aqueous solution (digestive juice)
9
Q
Acinar cells
A
secrete the enzymes (all of which are proteins)
Little berry secreting shit
10
Q
Duct cells
A
secrete the bicarbonate (NaHCO3-) buffered solution.
(found in the pancreas)
Ducks (Ducts) like bread (bicarbonate)
11
Q
Trypsinogen is an example of a zymogen. What is that? How is it activated?
A
A zymogen is an inactive form of an enzyme. Most pancreatic enzymes are produced as zymogens.
zymogen is like a wrapped candy bar.
12
Q
What is enterokinase and where is it found? Is it important?
A
Enterokinase (an enzyme itself) is present within intentional microvilli and converts inactive trypsinogen into active trypsin enzyme. Once active, trypsin activates other enzymes.
It is found within the plasma membrane of intestinal epithelial cells lining the duodenum.
13
Q
What is bile? Where is it produced? Where does it get stored?
A
Bile is constantly secreted by the liver and stored/concentrated by the Gall’s bladder. Bile salts are needed for fat emulsification. Bile is stored in the gallbladder.
14
Q
What is the first pass effect?
A
Detoxification of harmful compounds before entering into general circulation
15
Q
What happens in the large intestines?
A
Receives undigestable material (fiber) from the small intestine. Absorbs water and ions, houses gut microbiome
16
Q
Are the large intestines the same as the small intestines?
A
The small intestine primarily absorbs nutrients from food
The small intestine is involved in the digestion of food and absorption of nutrients. The large intestine is involved in the absorption of water and in the production of vitamins.
Small intestine to large intestine. Small intestine absorbs most nutrients.
17
Q
What is the gut microbiome? Is it important?
A
Located mainly in the large intestine (pH in the stomach and digestive enzymes in the small intestine prevent significant colonization)
1. Defense against pathogenic microorganisms
2. Production of short-chain fatty acids which are important for colonic health and function
3. Energy regulation
4. Vitamin synthesis
18
Q
What do antibiotics do to our gut microbiome?
A
Can alter the composition of gut microbiota for up to two years and by disrupting healthy flora (=dysbiosis)
19
Q
Abnormalities in microbiota are associated with?
A
- Obesity and other metabolic diseases
- Irritable bowel syndrome (IBS)
- Allergic disorders
- Clostridium difficile infection (CDI)
- Colonization by multiple drug-resistant organisms (MDRO)
- Neuropsychiatric illnesses
20
Q
What is a fecal transplant?
A
The introduction of donor microbiota alters the gut microbiota of the recipient.
- Highly efficacious for treating recurrent CDI
- Potential for treatment of IBS
- Mice models show potential for use as a treatment for obesity.
21
Q
Where do ulcers come from?
A
Gastric ulcers are:
- Formerly believed to be a psychosomatic disease brought on by stress or anxiety and aggravated by spicy foods.
**Helicobacter pylori **
cause the majority of stomach ulcers and gastric cancer.
22
Q
What are some of the functions of the kidney?
A
- Maintain the water balance of the body
- Regulate the concentration of electrolytes in the plasma
o Cations: Na+, K+, Ca2+, Mg2+, H+
o Anions: Cl-, HCO3-, SO42-,PO43- - Maintain proper volume of the plasma, which directly affects blood pressure (higher volume= higher pressure)
- Regulate pH of the blood plasma
- Maintain proper osmolarity of the blood plasma
- Excrete toxic by-products of metabolic reactions such as urea, uric acid, and creatinine
- Excrete toxins are absorbed from the environment in foods, drugs, etc.
- Secrete the hormone erythropoietin (EPO) which stimulates the production of new red blood cells (RBCs)
23
Q
What is erythropoietin (EPO)?
A
Stimulates the production of new red blood cells (RBCs)
24
Q
What does renin do?
A
Cuts angiotensinogen into the shorter peptide known as angiotensin I.
25
What is obligatory water loss?
- 400-500 ml of urine/day will be produced regardless of intake
- This is because your body has to continuously filter and purify the blood plasma.
26
Kidney tubules are made of what?
Epithelial cells rolled into tubes.
27
Why would transport be needed in the kidney tubules?
Blood plasma is filtered into kidney tubules, and this ultrafiltrate is then modified as it passes down the tubule.
28
How does blood flow to the kidneys relate to the size of the kidneys?
Blood flow to the kidneys (at rest) is disproportionately high, considering the small size of the kidneys.
29
Why do the kidneys get so much blood?
Cardiac Output (C.O.)= five liters of blood/minute at rest
Blood flow to kidneys is 1.140 liters/minute. This is 22% of C.O., yet the kidneys compose only 1% of body weight.
This is needed because the kidneys primary function is to filter waste products and excess fluid from the blood.
30
How does urine flow?
Urine flows from the renal pelvis of the kidneys through smooth muscle-walled tubes called ureters which deliver urine to the bladder.
31
How does urine move down the ureters to the bladder?
Ureters undergo peristaltic contractions that squeeze urine to the bladder.
Each ureter has a one-way valve at the point where it enters the bladder that prevents urine from flowing back up into the ureter and renal pelvis.
32
Structure of the nephron:
- The glomerular (Bowman’s) capsule
- The kidney tubule
- All of the associated capillaries
33
What is the vasa recta?
a group of blood vessels in the kidney that supply oxygen and nutrients to the medulla and also help regulate urine concentration.
34
Afferent vs efferent arterioles
Afferent arteriole feeds blood into the glomerulus
Efferent arteriole exists to shuttle filtered blood from the glomerulus back into the main circulation.
35
How does blood plasma get filtered into the proximal convoluted tubule? Where does it go after that point?
Through the glomerulus then it goes through the efferent arteriole which then branches into a network of capillaries called the peritubular capillaries
36
How is ultrafiltrate made? What is the filter apparatus (what makes it up)?
Blood plasma is driven to become ultrafiltrate, which is pushed into the lumen of Bowman’s capsule. The filter apparatus of nephrons is composed of fenestrae, the extracellular basement membrane, and the slit diaphragms located between adjacent pedicels.
37
How are proteins retained in the blood plasma?
Plasma proteins cannot enter the filtrate because they cannot pass through the basement membrane, which is composed of negatively-charged extracellular matrix (ECM) proteins that electrostatically repel the negatively charged plasma proteins.
38
What is happening in the descending limb of the loop of henle?
The descending limb is highly permeable to water, but not to salt. So, water is easily reabsorbed here and solutes are not readily reabsorbed.
39
What is happening in the acending limb of the loop of henle?
The ascending limb, primarily sodium chloride (salt), is actively reabsorbed from the filtrate, diluting the urine while being impermeable to water.
40
Where can excess potassium be added so it will be excreted in urine?
Can be actively transported (i.e., secreted) into the filtrate within the cortical portion of the collecting duct to eliminate excess K+ from the body, thereby regulating the K+ of plasms and ISF at ~5mM.
41
How is urine concentrated? This has to do with the collecting ducts, what happens here?
Concentrated urine enables the body to retain water and not become dehydrated, all while forming the urine and thereby eliminating wastes and toxins.
42
What is the relationship between ADH and aquaporin channels?
Aquaporin channels (aka ‘water channels’) stored within intracellular vesicles are reversibly inserted into the plasma membrane of collecting dust cells by the process of exocytosis. This insertion is triggered by antidiuretic hormone (ADH) secreted by the posterior pituitary gland.
Once sufficient water has been reabsorbed back into the ECF, secretion of ADH stops, Aquaporin ADH stops, and Aquaporin Channels are retracted back into intracellular vesicles (through the process of endocytosis)
43
Do you understand where the juxtaglomerular apparatus is? What does it do?
The juxtaglomerular (J-G) Apparatus is composed of granular cells within the walls of afferent arterioles, and the macula densa, which are specialized epithelial cells of the distal tubule.
The function of the J-G Apparatus is to regulate blood pressure.
44
Review the Renin-Angiotensinogen-Aldosterone system. What roles do the kidney, liver,
and lungs play? Does this system increase or decrease blood pressure?
Your kidneys, adrenal glands, and posterior pituitary glands work together to regulate your water content, your salt content, and your blood pressure. Altogether, they compose the renin-angiotensin-aldosterone system. Increases blood pressure.
45
Does ANP do the same thing as renin?
No, they have opposite effects. ANP decreases blood pressure
46
Why is it said that urine from a diabetes mellitus patient would attract ants?
Because the urine contains extra sugar. The ants could detect the sugar in the urine.
47
Type 1 diabetes
Type 1: “Insulin-dependent DM”
- Relatively uncommon (~10% of all DM cases)
- Due to insufficient secretion of insulin
- Cause: Insufficient insulin is due to loss of pancreatic beta cells, thought to be due to auto immune attack causing beta cell death.
48
Type 2 diabetes
Type 2: “Non-Insulin-dependent DM”
- Most common type (~90% of all cases).
- Due to insufficient response to insulin.
o DM2 is the same as “Insulin-Resistance”
49
Gestational diabetes mellitus
- Occurs in up to 9% of pregnancies
- Results when a mother’s pancreatic beta cells cannot secrete enough insulin to meet the needs of both mother and fetus
- Usually resolves after delivery.
- Increases the probability (by 3-7 times) that the mother will develop DM2 within 5-10 years.
50
There are five steps that exist between insulin binding to a receptor and glucose being
taken up by cells. What happens if something in the process doesn’t work?
1. Insulin binding to the insulin receptor
2. Receptor autophosphorylation
3. Recruitment of signaling proteins (like IRS)
4. Phosphorylation cascade activating GLUT4 translocation
5. Glucose transport through the plasma membrane via GLUT4
If any of the proteins that act downstream from the Insulin Receptor are missing or mutated such that they can no longer function, insulin resistance can result.
51
How does exercise reduce glucose concentrations in the blood?
Muscles can absorb glucose from the blood and use it for energy
Exercise increases insulin sensitivity, which helps muscle cells use insulin to take up glucose.
During exercise, your body burns glucose from your bloodstream and from stored glucose from your bloodstream and from stored glucose in your muscles and liver.
52
What role does adipose tissue play in insulin resistance?
1) Leptin= promotes insulin resistance
2) Resistin= promotes insulin resistance
3) Retinol binding protein 4= promotes insulin resistance
4) Tumor Necrosis Factor a (TNFa)= promotes insulin resistance
5) Adiponectin= reduced insulin resistance
6) Apelin= appears to reduce insulin resistance
53
What are adipokines? Which ones will reduce insulin resistance?
Fat cells (adipocytes) secrete hormones. These are known as adipokines.
Adiponectin, Apelin
54
Is diabetes insipidus (DI) the same as diabetes mellitus (DM)? What is polyuria? Which one is it found in (DI or DM)?
Diabetes insipidus (DI) is completely different than Diabetes mellitus (DM). Don’t confuse the two.
Both DM and DI exhibit polyuria, but the cause of polyuria is different in each case.
In diabetes mellitus, polyuria is due to an osmotic effect produced by the abnormal presence of glucose in the urine.
55
Neurogenic diabetes insipidus (DI)
- “arising from the nervous system”
- Caused by insufficient secretion of ADH (anti-diuretic hormone) from the posterior pituitary gland
- ADH makes kidney tubules reclaim more water from the nascent (i.e., forming) urine.
56
Nephrogenic DI
Nephrogenic diabetes insipidus is a kidney condition. Your body fails to respond properly to a natural hormone called antidiuretic hormone (ADH). Therefore, it produces too much urine, which can cause rapid, sometimes dangerous dehydration.
57
Primary sex organs
Primary sex organs (gonads)
- Produce gametes (testes or ovaries)
58
Secondary sex organs
Secondary sex organs: organs other than gonads that are necessary for reproduction
- Male: system of ducts, glands; penis delivers sperm cells
- Female: uterine tubes, uterus, and vagina receive sperm and harbor developing fetus.
59
Terms you gotta know about men
penis
testes
scrotum
seminal vesicles
prostate
bulbourethral glands
Seminiferous tubules
‾Epididymis
Vas deferens
Urethra
60
Terms you gotta know about women
vulva
labia majora
labia minora
vestibular glands (bartholin's glands)
urethral orifice
vaginal orifice
clitoris
hymen
ovaries
oviduct (fallopian tubes)
Uterus
Cervix
Vagina
61
The vagina has a very specific microbiome. Why would we need a microbiome there? Is
douching important?
A low pH environment is maintained. Douching is unnecessary because the vagina is self-cleaning.
62
During development of the embryo, what causes the development of mesonephric ducts (Wolffian ducts)?
Gonad development
63
What causes the development of paramesonephric ducts (Müllerian ducts)?
Initially, a fetus is sexually undifferentiated.
- Gonads begin to develop at five or six weeks as gonadal ridges.
- Two sets of ducts adjacent to each gonadal ridge
o In males, mesonephric ducts develop into reproductive tract; paramesonephric ducts degenerate
o In females, paramesonephric ducts develop into the reproductive tract; mesonephric ducts degenerate.
64
What is TDF?
Testes-determining factors (TDF) that initiate the development of testes.
65
What is cryptorchidism?
a condition in which one or both of the testes fail to descend from the abdomen into the scrotum.
66
Male and female organs develop from the same embryonic structures. Do you understand
why the penis is homologous to the clitoris?
They both develop from the same embryonic tissue in the early stages of female development.
67
What is the scrotum homologous to?
The labia majora
68
Gonadotropins will cause the gonads to secrete what? How constant is the production of
these hormones?
Gonadotropins, specifically luteinizing hormone (LH) and follicle-stimulating hormone (FSH), stimulate the gonads to secrete sex hormones like estrogen and progesterone in females, and testosterone in males;
Hormones are not constant.
69
How do sperm form in the seminiferous tubules?
Seminiferous tubules where sperm are formed. Contain Sertoli cells that have receptors for fish, which stimulates spermatogenesis
70
Where would you find the least developed sperm?
The least developed sperm would be found within the seminiferous tubules of the testes,
71
Where would you find the most developed sperm?
the epididymis
72
What do sertoli cells do?
They respond to FSH which stimulates spermatogenesis
73
What do leydig cells do?
Lydig cells have receptors for LH, which stimulates Leydig cells to produce testosterone
74
Four sperm result every time a primary spermatocyte undergoes meiosis, how many eggs
result? Why is this?
Four sperm result from each primary spermatocyte. Less developed sperm (spermatogonia) are the periphery of the seminiferous tubule, and the more developed sperm are next to the lumen with their developing tails extended into the lumen.
75
How many eggs does a female have at birth?
Females are born with all eggs present. The process of making new eggs is stopped at birth. At birth, there are ~1~2 million oocytes.
76
How many eggs are present during puberty?
During puberty, there are ~400,000 oocytes. Only 400 ova are released during a woman’s life, the rest will die.
77
Once at puberty, what stage of meiosis are eggs at? When do they finish meiosis II?
Hormones cause the development of a few follicles each month. Primary oocytes will finish meiosis I.
The cell divides unequally, and polar bodies die. Meiosis II arrests at metaphase II.
78
How long does it take an egg to mature to the point they can be released (ovulated)?
Development from the primordial follicle to the ovulatory stage is almost a year.
79
Do you understand the development steps from primordial follicle to graafian follicles?
Takes 28 days. This is cyclic recruitment.
80
What determines which follicle will be the dominant one that gets released?
Follicle size, number of granulosa cells (supporting cells), Number of FSH receptors on the granulosa cells.
81
Follicular phase?
- Begins on the first day of menstruation
- The follicle matures and releases an egg
- Ends with ovulation
- Overlaps with menses and the proliferative phase of the uterine cycle
o The endometrium is shed and rebuilt.
82
Luteal phase?
- Beings with ovulation
- Corpus luteum development
- Ends with either pregnancy or luteolysis (degradation of the corpus luteum)
- Overlaps with the secretory phase of the uterine cycle
o Progesterone is released to maintain endometrium.
83
Menses' Phase?
- The endometrium is shed (bleeding)
- Lasts two to seven days.
- Triggered by low hormone levels (estrogen and progesterone)
84
Proliferative Phase
- Endometrium begins to thicken
- Phase ends after ovulation (day fourteen)
- Triggered by increased estrogen levels
85
Secretory phase
- The endometrium prepares for implantation
- Progesterone secreted for endometrium maintenance
86
Layers of the uterus?
Endometrium
- The inner layer of the uterus sheds during the menstrual cycle
Myometrium
- The middle, muscular layer of the uterus
Perimetrium
- Outer coat of the uterus
87
What role do fimbria play? Is the ovary attached to the fallopian tube?
Oviducts (fallopian tubes)
- It is not connected to the ovary but has fringe-like fimbriae that help eggs enter the tube. Fertilization usually occurs here.
88
How long do eggs have to be fertilized?
24 hours or they will die
89
When does an egg complete meiosis II?
The oocyte begins meiosis II before ovulation but completes it only if fertilized.
90
* How do sperm get out of the body? Do you understand the pathway of sperm?
- Sperm are produced in testes.
- When sperm have developed flagella they leave seminiferous tubules and enter epididymis where they mature.
- They leave the epididymis and enter the vas deferens.
- When stimulated, sperm is carried to behind the bladder where it will mix with seminal fluid (secretions from seminal vesicle, prostate and bulbourethral gland) and leave through the urethra.
91
After leaving the seminiferous tubules the sperm still need to mature, where do they go? Where
do the vas deferens take the sperm? Why must they travel to behind the bladder?
They enter the epididymis to mature. The epididymis to the urethra. It must travel behind the bladder because this is where the seminal vesicles, two pouch-like glands that contribute a significant portion of the fluid to the semen, are located.
92
Seminal vesicles
- Produce 45-80% semen volume
- Seminal fluid has fructose that nourishes the sperm
93
Prostate gland
- 15-30% semen volume
- Prostatic fluid has citric acid (a buffer), calcium, and coagulation proteins.
94
Bulbourethral glands
- Contributes only a small proportion
- Also called Cowper’s glands
- Lubricates urethra for semen passage
- Neutralized acidity from urine
- Might have some sperm in there.
95
There are no bones in the penis or the clitoris, but they can become erect. How is this possible?
Parasympathetic nerves secrete acetylcholine (ACh)
* ACh causes nitric oxide (NO) production.
* NO activates guanylyl cyclase (GC) enzyme.
* GC produces cyclic guanosine monophosphate (cGMP).
* cGMP closes voltage-gated Ca2+ channels in the smooth muscle walls of
arterioles within the penis (or clitoris).
* cGMP relaxes smooth muscle cells by decreasing cytoplasmic Ca2+
concentration.
* Relaxation of smooth muscle allows arteriole walls to dilate (i.e., expand)
and allow more blood flow into the penis (or clitoris), which are both
hydrostatic organs
