AP II Final Flashcards
(234 cards)
1
Q
Kidneys Conserving Water
A
most of the water and solute of the filtrate are reabsorbed or we would piss to death.
2
Q
amount of water filtered each day?
A
1700 Liters, we only have 5000 liters total so blood is filtered several times a day
3
Q
how much become filtrate? Piss?
A
180 liters becomes filtrate and only 1-2 liters become piss
4
Q
3 places of water absorption
A
proximal convoluted tubule (65%), nephron loop (17-25% and also generates the conc gradient in renal medulla, and collecting duct (reabsorbs thanks to conc gradient in medulla)
5
Q
osmosis
A
diffusion of water across a selectively permeable membrane toward areas of high conc.
6
Q
why do we need to diffuse water?
A
must diffuse from renal tubule into blood but original filtrate is isotonic with blood plasma and there for there is no reason for water to diffuse.
7
Q
Nephron Loop (loop of henle)
A
main function is to create a gradient of increasing osmolarity from the cortex to the medulla. This allows water to be reabsorbed by osmosis from the descending limb and the collecting duct as they run down into the medulla
8
Q
osmolarity
A
a measure of the osmotically active solute concentration
9
Q
how does nephron loop create conc. gradient?
A
by actively pumping salts into the medulla
10
Q
how does urea contribute to a hypertonic medulla?
A
the papillary duct is permeable to urea, when the urine gets here, the urea diffuses out into the medulla…responsible for 40% of the high osmolarity in deep renal medulla
11
Q
Distal Convoluted Tubule
A
also reabsorbs water and sodium and strongly influenced by hormones. (as collecting duct plunges into renal medulla, it encounters an increasingly “salty” interstitial fluid). It also secretes potassium and hydrogen ions
12
Q
Endocrine regulation of kidneys
A
if we need to conserve water, the kidneys excrete a hypertonic urine(if water is in excess then a hypotonic urine). This enables the kidneys to help maintain the homeostasis in terms of blood volume, pressure, and osmolarity.
13
Q
Water absorption is obligatory where? Voluntary?
A
Obligatory in PCT and nephron loop, voluntary in collecting duct and DCT (adjustable based off what we need) Hormones are crucial here.
14
Q
Antidiuretic (ADH)
A
1) stimulates reabsorption of water by kidneys. 2) produced by the hypothalamus but stored in and secreted by the posterior pituitary. 3)the main stimulus for ADH secretion is an increase in osmolarity of the blood plasma (detected by sensory receptors in hypothalamus) 4) increased ADH causes the walls of the DCT and collecting duct to become more permeable to water
15
Q
what would increase plasma osmolarity?
A
dehydration and salty foods
16
Q
aquaporins
A
vesicles that contain water channels, ADH stimulates these to fuse with the plamsa membrane and thus insert the aquoporins into the plasma membrane (makes it easier for water to move)
17
Q
When ADH is max we can produce what conc. of urine?
A
1200 mOsm/L
18
Q
what does decreased ADH cause?
A
aquoporins to be removed from the plasma membranes and brought back into the cell within the vesicles. this decreases permeability to water and thus more water is excreted in the urine.
19
Q
diabetes insipidus
A
condition in which a person doesn’t produce ADH = constantly excrete a large volume of very dilute urine. At risk of dehydration and dangerously low blood pressure
20
Q
Aldosterone
A
sodium ions are the major solute in the blood plasma. when blood conc. of sodium falls, so does osmolarity of blood. A drop in blood osmolarity inhibits ADH secretion w/ the effect that more water is excreted in the urine. Big drop in sodium may cause a dangerously low drop in blood pressure.
21
Q
aldosterone secretion
A
by adrenal cortex of adrenal gland in response to a decline in the blood sodium conc. This stimulates the reabsorption of sodium in the DCT and collecting duct in order to maintain homeostasis. Aldosterone is the “salt retaining hormone”
22
Q
effect of the movement of sodium
A
Cl- follows sodium and is passively reabsorbed, therefore water is osmotically attracted to sodium and chlorine
23
Q
effects on the body of aldosterone
A
retains salt and water, this helps maintain blood: osmolarity, volume, and presure
24
Q
Addison’s disease
A
individuals that cannot secrete aldosterone will die if untreated b/c of excessive loss of salt and water in urine. its secretion is due to decreased blood sodium, this is indirect and involves the juxtaglomerular apparatus, renin, and angiotensin
25
juxtaglomerular apparatus
specialized epithelium and smooth muscle cells near the glomerulus. detect the decline in blood flow thru afferent arteriole and respond by secreting the enzyme renin into the blood. renin is responsible for production of angiotensin II
26
effects of angiotensin II
stimulates blood vessels to constrict and adrenal cortex to secret aldosterone.
27
Natriuretic peptides
secreted in response to high blood pressure that stretches the heart walls, these oppose the action of aldosterone by inhibiting the reabsorption of sodium and water...help reduce blood volume and pressure.
28
Ureters
two muscular tubes that transport urine from kidneys to the bladder. retroperitoneal and firmly attached to posterior abdominal wall. this wall has a longitudinal and circular layer of smooth muscle, lined with transitional epithelium. transport urine via peristalsis and empty into bladder thru slit-like openings that prevent urine from being forced back during contractions
29
Bladder
hollow, muscular organ that temporarily stores urine (kidneys constantly secret urine). located inferior to peritoneum and stabilized by fibrous bands that anchor it to the pelvic bones. These ligaments connect the bladder to the umbilicus (carry blood to placenta during pregnancy)
30
Inferior point of bladder
region around uretheral opening is called the neck, neck has internal uretheral sphincter
31
3 layers of the bladder
mucosa - inner most layer of transitional eli over layer of reticular tissue (plump when empty and flat when full). muscular wall - three irregular arranged muscular layer (middle layer is circular and outer layers are longitudinal. and tough C.T. on outside
32
Urethra
drains bladder, conducts urine to outside of body. Lined with transitional, stratified columnar, and stratified squamous.
33
external urethral sphincter
muscular band around urethra that acts as a valve to control urine
34
Differences in male/female urethras
longer in males (20 cm as opposed to 4 cm in females) runs along prostate gland in males, and helps with passage of semen (also reproductive)
35
micturition
voiding of urine from the body, controlled by two valves (interior [involuntary] and external [voluntary] urethral sphincters)
36
bladder collection
collects until about 200 mL have accumulated, this stimulate stretch receptors in the wall of the bladder. receptors stimulate contraction via parasympathetic NS...now consciously aware that we need to pee
37
Steps of urinating
voluntarily relax external urethral sphincter, this triggers internal sphincter to relax as well. If you don't want to pee you keep external sphincter contracted and this works until another 200 mL have collected. we lose the ability to control this once urine gets forced into superior urethra.
38
Incontinence
lack of voluntary control over urination, normal in kids, in adults its a result of spinal cord injury, bladder irritability, or trauma to sphincters.
39
Digestive System provides 2 essentials
fuel that keeps our cells running (sugars and fats for ATP) and building blocks needed for cell growth and repair (amino acids, fatty acids, minerals)
40
Components of Digestive system
GI tract, oral cavity, pharynx, esophagus, stomach, small and large intestines. And accessory organs such as teeth, tongue, salivary glands, liver, and pancreas/gall bladder
41
Functions of Digestive Tract
Mechanical processing, digestion, secretion, absorption, excretion, and protection
42
Mechanical processing of D.S.
tearing, crushing, mixing foods. this makes it easier to propel food along GI tract and exposes more surface area which aids enzymatic digestion
43
Digestion of D.S.
chemically breaking the food down into smaller organics that we can absorb. Some things (glucose) can be absorbed as is, other things (proteins and fats) must be broken down.
44
Secretion of D.S.
secrete water, acids, and enzymes, buffers and salts into the GI tract.
45
Absorption of D.S.
nutrients and water are absorbed across the digestive epithelium and into the interstitial fluid where blood vessels pick them up and distribute them
46
Excretion of D.S.
the GI tract and accessory organs discharge waste into the tract which is eventually ejected from the body as feces
47
Protection of D.S.
lining of the GI tract protects the surrounding tissues: corrosive effects of enzymes and acids, mechanical stresses or abrasions, and bacteria that are ingested or live in GI tract.
48
Peritoneum
largest portion of the abdominopelvic cavity. Most digestive organs are covered with visceral peritoneum (serosa). Parietal peritoneum lines inner surface of body wall. Two layers slide past each other thanks to peritoneal fluid
49
Messentary
double-sheet of peritoneal membrane that suspends the GI tract and stabilizes the position of some organs
50
aerolar tissue in digestive system
provides passage of blood vessels, nerves, and lymphatic vessels
51
Messentary proper
thick mesentery that stabilizes the small intestine
52
Greater Omentum
large fold of the dorsal mesentery of the stomach (hangs anterior to intestines) Fat within it cushions and protects the abdominal organs (also storage of fat)
53
Histology of digestive tract: Mucosa
innermost lining is a mucous membrane and consists of an epithelium on top of the mainz propria
54
Histology of digestive tract: Epithelium
where abrasion is the worst we have stratified squamous, where absorption occurs we have simple columnar (goblet cells), and constantly renewed by divisions of epithelial stem cells
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Histology of digestive tract: Lamina Propia
areolar tissue that contains blood vessels, sensory nerve endings, lymphatic vessels, smooth muscle tissues, and scattered areas of lymphoid tissue. Most areas of GI tract contain smooth muscles and elastic fibers called muscular is mucosae that changes shape of the lumen and creates ridges/grooves of the tract.
56
Histology of digestive tract: Submucosa
layer of loose CT that surrounds the mucosa, contains large blood and lymph vessels, exocrine glands secrete enzymes and buffers into the lumen of the GI tract. Outter portion contains a network of nerve fibers called submucosal plexus (sensory neurons and ANS neurons)
57
Histology of digestive tract: Muscularis externa
outside of submucosa is layer of smooth muscles, made of inner circular layers and outer longitudinal muscles. Creates movement that mixes the food and moves the food bolus down the GI tract. parasympathetic activity increases the muscular action and sympathetic inhibits it. sandwiched btwn circular and longitudinal layers of muscle is the myenteric plexus (network of neurons that regulates the GI tract)
58
Histology of digestive tract: Serosa
same as visceral peritoneum, outermost layer of most of the digestive tract (simple squamous)
59
How food bolus moves along digestive tract
smooth muscle of the GI tract contains specialized smooth muscle cells, called pacesetter cells, that spontaneously depolarize, then a chain of depolarization moves like a wave.
60
Peristalsis
wave a smooth muscle contractions that move the bolus along the length of the GI tract. Works the same way a worm crawls
61
Segmentation
uncoordinated contraction of the muscles that serves to break up the bolus and mix it with the intestinal secretions
62
Neural regulation
controls the contractions of the GI tracts and many of the secretory functions. Due to: CNS which controls large-scale peristalsis, complex neuronal networks in the GI tract and would involve the myenteric plexus
63
Hormonal mechanisms
the mucosa may contain enteroendocrine cells scattered among the columnar cells, secrete hormones that regulates the GI tract and accessory organs. Produce at least 18 hormones that affect virtually every aspect of digestion
64
Local mechanisms
messengers like histamine and prostoglandins may coordinate the activity of a small area of the GI tract. Release histamine from the lamina propria of stomach to secrete acids
65
What cells secrete histamine? In what type of tissue?
mast cells in aereolar tissue
66
Oral Cavity Functions
sensory analysis of material (touch, temp, pain, taste). mechanical processing (teeth and tongue), lubrication (salivary glands and mucous to dissolve food and activate taste receptors), limited digestion of carbs and lipids
67
Tongue
besides compressing and manipulating food and sensory analysis, it also secretes mucins (proteoglycans responsible for lubricating mucus) and the enzyme lingual lipase (starts lipid digestion in the oral cavity and continues to digest (has a broad pH range)
68
Salivary Glands
3 pairs: parotid glands - anterior to earlobe, has salivary amylase that breaks down starch. sublingual glands - below tongue, produces mucous secretion that is a lube and pH buffer. And submandibular glands - inner surface of mandible, produces most saliva (70%) and a mucous secretion with salivary amylase
69
Functions of saliva
lubricant, begins starch digestion via salivary amylase, some saliva is released to help flush out the oral cavity and keep it clean, as well as buffers in saliva that counteract the acids produced by oral bacteria to keep pH at 7. IgA and lysozyme in salvia help control the bacteria
70
What is mumps?
viral infection of the salivary glands
71
Teeth
chewing helps break down food and saturate it with salivary secretions and enzymes
72
Regions of the tooth
crown - upper, exposed portion, neck - main part, and root - base of tooth and embedded into the bone of maxilla or mandible
73
Teeth Regions (internal)
held in bony sockets by periodontal ligaments, DENTIN - mineralized matrix that makes up the bulk of a tooth, ENAMEL - covers the dentin of the crown, hardest biologically made substance known. CEMENTUM - bone like material that covers the dentin of the root. PULP CAVITY - interior chamber of tooth with cells, blood vessels, and nerves
74
Dental succession
deciduous teeth - temp teeth (20 and lost btwn ages 6-13)
| adult teeth - 12 molars gained to bring total to 32
75
wisdom teeth
3rd molars that come in last and may not have room for them.
76
Other structures of Teeth
GINGIVAE - ridges of oral mucosa around the base of the teeth (tight to the periosteum of maxilla and mandible)
HARD PALATE - provides a stiff surface against which the tongue can work to compress food
SOFT PALATE - posterior to hard palate, uvula is process that dangles from the posterior margin of the soft palate (keeps you from prematurely entering the pharynx) and blocks the nasopharynx during swallowing.
77
Pharynx
extends from just behind nasal cavity to region of mouth down to larynx and esophagus. mostly lined with stratified squamous for protection from abrasion, chemicals, and pathogens. common passage for air, food, and liquids
78
Esophagus
conducts food and drink from pharynx to the stomach, posterior to the trachea. Prevents air from entering the stomach and leaking up into the trout. needed b/c no sphincter in throat.
79
Histology of Esophagus
mucosa is made of stratified squamous epi, submucosa contains mucous glands, muscular is externa has inner circle of smooth muscle for peristalsis.
80
Stomach: Four major functions
storage of food, mechanical breakdown of food (thru churning), digestion via acids - HCl acid to breaks down food, allows salivary amylase/lipase to continue digestion until too acidic, once too acidic this triggers pepsin. And finally production of an intrinsic factor - glycoprotein so the small intestine can absorb vitamin B
81
What does not occur in the stomach?
No absorption of nutrients
82
Anatomy of Stomach
4 regions: cardia - small part consisting of first 3 cm of esophagus. funds - superior to the end of the esophagus. Body - biggest part, mixing tank, with gastric glands that secrete acids and enzymes. pylorus - sharply curving portion of stomach that regulates passage of chyme into duodenum.
83
chyme
viscous, highll-acidic soupy mixture of partially digested food in the stomach.
84
Histology of stomach
lined with simple columnar epithelium. produces mucus that protects it from acids and enzymes.
85
gastric glands
occur deepen the gastric pits of the fundus and body. Contain two secretory cells: parietal cells and chief cells.
86
Parietal Cells
secrete intrinsic factor and HCl. hydrogen ions generated inside parietal cell from carbonic acid, formed from CO2 and water. Hydrogen ions are tun transported into the lumen, bicarbonate is ejected into interstitial fluid that brings Cl into the parietal cell. This diffuse down their conc. gradient thru simple leak channels into the lumen of gastric glands and the two ions combine to form HCl.
87
alkaline tide
when gastric glands are especially active so bicarbonate can enter the interstitial fluid, that blood pH increases noticeably. Parietal cells generally keep the stomach pH at 7.5
88
Functions of acidic stomach
kills most microbes ingested with the food, breaks down proteins, breaks down tough plant cell walls and CT in meat, and essential for activating pepsin.
89
Chief cells
secrete an inactive proenzyme called pepsinogen, once it encounters the acid of the stomach, its converted into pepsin (which digests proteins). This prevents active enzymes from damaging the structure it secretes.
90
Pyloric Glands
within the pylorus of the stomach, secrete mostly mucus and several hormones (not acids or enzymes) .
91
gastrin
hormone that stimulates: secretions of both parietal and chief cells and the contractions of the stomach wall to mix the chyme.
92
Small Intestine
where most digestion and absorption (90%) occurs here (with help of pancreas and liver)
93
Anatomy of small intestine
15 feet long, supported by the mesentery proper thru which blood vessels, lymphatic vessels, and nerves reach the small intestine. 3 segments: duodenum, jejunum, and ileum
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Duodenum
initial and shortest segment, mixing bowl for chyme in stomach and the secretions of the pancreas and liver. Main function is to neutralize the acidity of the chyme before it can damage the epithelial lining of the SI.
95
Jejunum
middle segment - 5 feet long, where most digestion and absorption occurs.
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Ileum
final segment and the longer (9 feet). ends at ileoceal valve which controls the passage of material into the start of the large intestine or cecum. Contains lymphoid tissue called Peyer patches - lymphocytes here protect the small intestine from the bacteria that normally inhabit the large intestine.
97
Histology of Small Intestine
Circular folds that line the small intestine, unlike rugae the circular folds are permanent features that do not disappear when the SI fills up. This greatly increases the surface area for absorption.
98
Intestinal Villi
small, fingerlike projections of the mucosa are covered with simple columnar cells bearing densely packed microvilli. Numerous goblet cells occur btwn the columnar cells and secrete mucus onto the lining of the SI. Plicae, vili, and microvili together give us a SI with a surface area of 2200 square feet.
99
Each villus contains
1) network of capillaries into which nutrients are absorbed (then delivered to liver via hepatic portal circulation) 2) a nerve ending. 3) and a lacteal which transports absorbed lipids
100
Intestinal secretions
numerous mucous glands in duodenum produce mucus which protects the epithelia from the acidity of chyme. Contains bicarbonate ions that neutralizes the pH. pH is btwn 1-2 at start but is at 7-8 at the end. Usually the secretions begin well before the chyme arrives so protection is in place.
101
Hormones released by the Small Intestine
gastrin, cholecystokinin and secretin. Enzyme are also released from shed epithelial cells and enteropeptidase which activates the pancreatic enzyme tripsinogen.
102
Organ associated with the Small Intestine
Pancreas, Liver
103
Pancreas Structure
located posterior to stomach, lumpy and lobular structure (wrapped in thin capsule of connective tissue) Has acinar cells that are simple cuboidal cells which make up the bulk of the pancreas and produce enzymes which do digestive work.
104
Pancreas functions
produces a pancreatic juice: mixture of water, digestive enzymes and buffers thru pancreatic duct to the duodenum.
105
Pancreatic Juice from Hormones of duodenum
presence of chyme stimulates endocrine cells of duodenum to release secretin. Cholecystokinin stimulates pancreas to produce and release pancreatic enzymes. Anticipates chymes arrival.
106
Examples of Pancreatic Enzymes
pancreatic alpha-amylase : breaks down starches. Pancreatic lipase: breaks down complex lipids so fatty acids can be destroyed. Nucleases: break down DNA or RNA. Protease: breaks down large proteins (tripsinogen). Peptidases: break small peptides into individual amino acids
107
Trypsinogen
once activated by enteropeptidase into trypsin, it not only breaks down proteins but also activates many other proenzymes
108
Liver: Gross Anatomy
largest internal organ, most of its bulk is on the right side of the body, divided into a right and left lobe. Receives arterial blood via hepatic artery and receives venous blood via hepatic portal vein which carries blood coming from stomach, small/large intestines.
109
Histology of the Liver
each lobe is divided into 100,000 hexagon shaped lobules (the functional unit of the liver). the cells of the liver are called hepatocytes - in a liver lobule the hepatocytes are arranged like the spokes of a wheel.
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Histology of the Liver: Part 2
sinusoidal capillaries run btwn the spokes and drain into the central vein. At each corner there is a hepatic triad which has 3 parts: branch of hepatic portal vein, branch of hepatic artery, and branch of the bile duct.
111
What do hepatocytes absorb and secrete?
absorb solutes from the blood, and secrete plasma proteins into the blood.
112
Bile Duct System
bile is produced by hepatocytes and flows into the bile ductules, eventually empty into the common hepatic duct which leaves the liver. From here the bile either: goes into the bile duct which delivers bile to the duodenum via the duodenal papilla or goes into the gall bladder for storage.
113
Functions of the Liver
like the kidneys, the liver receives 25% of cardiac output, and it has a major influence on the composition of the blood. Nutrient reabsorption, Waste and toxin removal/storage, and bile production
114
Nutrient regulation
hepatocytes regulate blood glucose levels, regulates circulating levels of triglycerides, fatty acids, and cholesterol. Removes excess amino acids from blood stream to make proteins or synthesize glucose, stores fat-soluble vitamins, and stores excess iron as ferritin.
115
Waste and toxin removal and storage
neutralizes the toxic ammonia produced during amino acid metabolism by converting it into urea. Other waste products and toxins are also removed from the blood by the liver and either inactivated, stored, or excreted in bile. Inactivate drugs.
116
Kupffer cells
phaygocytize old RBCs as well as pathogens, can initiate an immune response thru antigen-presentation, removes and breaks down circulating antibodies, main site for removal and recycling of hormones, plays an important role in synthesis of calcitrol.
117
Bile production
liver synthesizes bile, which may be stored in the gall bladder, or excreted into the duodenum. Bile consists of water, with some ions, bilirubin (from broken down hemoglobin), cholesterol, and a variety of lipids known as bile salts.
118
Function of Bile
most lipids in our diets are not water soluble, so churning creates large lipid drops which protects the lipids from digestive enzymes, bile salts break large lipid drops into tiny drops thru emulsification. Increasing collective surface area so digestive enzymes can digest lipids, helps with absorption.
119
Gallbladder Anatomy
hollow, pear shaped organ with muscular walls located in the posterior surface of the right lobe of the liver.
120
Gallbladder Functions
stores and concentrates bile prior to its excretion into the duodenum. Released into duodenum only when stimulated to do so by release of the intestinal hormone cholceystokinin (w/o it all the bile goes to gallbladder for storage).
121
What happens when chyme enters the duodenum?
cholecystokinin is released, this stimulates gall bladder to contract and forces bile into the duodenum (chyme with large amounts of lipids stimulates an even greater secretion of cholecystokinin.
122
Gallstones
deposits of insoluble, crystalline bile salts that form when the bile becomes too concentrated. If large they can damage the wall of the gallbladder or block common bile duct (maybe surgically removed)
123
Cecum of the large intestine
pounch like beginning of the large intestine on the right side of the body, contents enter here after passing through the ileocecal valve, the slender, hollow appendix is attached to the posteromedial surface of the ocean. (appendix contains lots of lymphoid tissue hence, functions in immunity)
124
Colon of the large intestine
largest part of the large intestine, wall forms a series of pouches called hausfrau which allow the colon to expand and contract. 3 separate longitudinal bands of smooth muscle called teniae coli, run along the outer surfaces of the colon. Muscle tone within these muscular bands creates the haustra
125
4 regions of the colon
ascending (superior from cecum to liver on right side), transverse (runs laterally across abdomen from right to left), descending (runs inferior down to iliac fossa), and sigmoid (S shaped segment only 6 inches long)
126
Rectum of Large intestine
last 6 inches of large intestine, an expandable region for temp. storage of feces. Starts with simple columnar epithelial but near anus changes to stratified squamous, the muscular is extern in this area forms the internal anal sphincter, and the external anal sphincter.
127
Histology of Large Intestine
unlike small intestine, has no villi, wall is much thinner and does not secrete enzymes. Contains lots of mucous cells and scattered lymphoid nodules. mucus provides lubrication for the mvmnt of the feces which more dry and compact.
128
Functions of Large Intestine
reabsorption of water and compaction of intestinal contents into feces, excessive reabsorption leads to constipation, too little = diarrhea. Absorption of vitamins liberated by bacterial action.
129
Absorption of organic wastes
bacteria convey bilirubin into urobilinogen, some is absorbed in blood and excreted into urine. Bacteria also break down the remaining peptides and in the process generate ammonia and hydrogen sulfide. Much of ammonia is absorbed and sent via hepatic portal system to liver.
130
Digestion
meals are usually a mixture of carbs, proteins, lipids, water, salts, minerals, and vitamins.
131
What happens to large organics before digestion?
must be broken down, most are large complex chains of simpler molecules (proteins into amino acids)
132
Protein Break-down
chains of amino acids, starch/glycogen are chains of simple sugars, lipids are chains of fatty acids, nucleic acids are chains of sub-P-nitrog bases. Digestive enzymes break the bonds btwn the simpler building blocks in a process called hydrolysis.
133
What gets absorbed without modification?
water, salts, minerals, and vitamins
134
Carb digestion and absorption
complex carbs are broken down by salivary amylase and pancreatic alpha-amylase into disaccharides or trisacchirides. Then brush-border enzymes finish the digestion by breaking them down into simple sugars. Then thru facilitated diffusion the sugars are absorbed into capillaries
135
What if in adulthood a persons mucosa stops producing lactase?
they become lactose intolerant
136
Lipid digestion and abrosption
lingual lipase digests fats by breaking off two fatty acids, only 20% have been digested by the time chyme enters the duodenum b/c fat droplets are too large...emulsification by bile salts makes the digestion easier. Digested lipids, hydrophobic, diffuse into intestinal vili...get protein coating called chylomicrons
137
chylomicrons
protein coating of digested lipids that are transported into the lacteal and from there eventually enter the venous blood supply via the thoracic ducts.
138
Protein digestion and absorption
mechaincal/chemical breakdown begins protein digestion, acidity also activates pepsinogen (from stomach's chief cells) into pepsin which breaks peptide bonds. In small intestine enteropeptidase activates trypsinogen into trypsin. Proteins broken down into free amino acids which are absorbed into intestinal villi and enters capillaries via facilitated diffusion, then to liver.
139
Water Absorption
typically the GI tract secretes far more water than we acquire in our food/drink. Ingest 2 liters of water a day, but 7 liters are added via saliva, mucus, stomach secretions, bile, pancreatic juice, and intestinal secretions. Almost all water is reabsorbed via osmosis in small and large intestine, by following nutrients.
140
Ion absorption: Sodium
Sodium is absorbed via simple diffusion, active transport. Greater the conc. of sodium in food, the more absorption and gain of water through osmosis (aldosterone).
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Ion absorption: Calcium
active transport. calcitrol increases the rate or reabsorption.
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Ion absorption: others (potassium, chloride, magnesium, iron)
via diffusion, active transport, or carrier-mediated transport.
143
Testes
form within the body cavity near the kidneys and gradually move lower as fetus grows. In 3rd trimester they enter the scrotum.
144
Spermatic cords
these cords run btwn the testes and inguinal canal (passageway through the abdominal muscles)...consist of any outer layer of CT and muscle covering the ductus deferens, blood vessels, lymphatic vessels and nerves
145
Scrotum
each testis lies in a separate chamber, this limits the spread of infection, has smooth and skeletal muscles. Muscles are responsible for moving testes closer to or farther away to body to control temp.
146
pampiniform plexus
network of veins surrounding the testiculary artery, dolls the arterial blood.
147
structure of testes
tunica albuginea a dense ayer of connective tissue covering the testes and divides each into a series of lobules. Each contains hundred of tightly coiled seminiferous tubules where sperm are produced
148
sustenocular cells
occur within the seminiferous tubules and support the formation of sperm
149
rete testis
is a complex network of tubules at superior end of the testes into which the seminiferous tubules discharge their sperm. From the tete, sperm are conducted to the sphincter
150
interstitial cells
occur in the aerolar tissue between the seminiferous tubules, they produce androgens
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Spermatogenesis
the process of forming spermatozoa, begins at the outermost layer of cells in the seminiferous tubules, daughters cell move toward the lumen
152
Consists of three basic steps
Mitosis, Meiosis, and Spermiogenesis
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Mitosis
one cell divides into two, the daughter cells are genetically identical. one daughter cell remains to continue functioning as a stem cell, other becomes primary spermatocyte
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Meiosis
one cell divides into four, each daughter cell is different and has only half the genetic material (23).
155
Spermiogenesis
process in which spermatid matures into a spermatozoon (sperm)
156
Steps of meiosis
during interphase I primary spermatocytes replicate their DNA, thus each of the 46 chromosomes now has 2 duplicate chromosomes
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DNA make up
sugar phosphate sugar with AGTC
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prophase I
chromosomes condense and nuclear envelope disintegrates
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tetrads
homologous chromosomes join together (synapse)
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crossing over
swap some genetic material
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metaphase I
homologous pairs move and line up in middle of cell
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anaphase I
homologous pairs separate, not duplicate chromatids. 2 daughter cells with only half as much DNA (secondary spermatocytes)
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interphase II
chromosomes do not get replicated (copied)
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Second meiotic division is same as....
mitosis, this time chromosomes line up singly along midline, duplicate chromatids do separate in anaphase II
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second meiotic division results
two secondary spermatocytes divide to form four total spermatids. male can easily produce over 10 million different kinds of sperm
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3rd spermiogenesis
process in which spermatids differentiate into physically mature spermatozoa, changes from round shaped cell into streamlined shape, flagellum grow, and free themselves from sustenacular cells. Not functional at this point.
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Sperm Anatomy: 3 regions
head - nucleus with 23 densely packed chromosomes/acrosomal cap. middle - mitochondria for ATP to power tail. tail - flagellum that moves in a complex, corkscrew motion
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acrosomal cap
tip of the head that contains enzyme for fertilization
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Mature sperm don't have what?
no ER, no Golgi, no lysosomes, no peroxiosomes, no stored glycogen. Makes it smaller and faster, but mean it must absorb energy from fluid.
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Epidiymis Structure
copied tube bound to the posterior border of each testis, cilia create fluid mvmnt that transport immobile sperm from tete testis to epididymis. psuedostratified columnar ww/ distinctive stereocillia (huge surface area)
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Epidiymis Functions
stores sperm, absorbs and recylces damaged sperm, moves sperm along via peristalsis and fluid mvmnt. Adjusts the composition of the guild that the sperm are bathed in.
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Ductus Deferens: Structure
begins at the tail of the epididymis and as part of spermatic cord it ascends through the inguinal canal, curves along ladder, and empties into the ejaculatory duct. lined with psuedostraitifed columnar, has smooth muscle that moves sperm via peristalsis
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vascetomy
surgical removal of a segment of the ductus deferens near each testis, male is not sterile.
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ejaculatory duct
starts where ductus deferens and the duct seminal gland join, runs thru prostate gland before emptying into urethera
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urethera
runs from the urinary bladder thru thee tip of the penpis, common passage way for both urine and semen, varies from transitional to stratified columnar to stratified squamous.
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urethera; 3 types
prostatic - thru prostate gland, membranous - thru body wall, and spongy - through penis
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Seminal vessicles
glands located on posterior of bladder, superior to prostate gland, drain into ejactulatory duct near where vas deferenes drain, and secretion account for majority (60%) of semen.
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Secretions of seminal vessicles
lots of fructose for energy, prostoglandins to stimulate smooth muscle, prosemenogelin to form sperm plug, and all secretions are alkaline to neutralize the acidity of vagina. In seminal vesicles, sperm finally start to swim.
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Prostate gland
muscular, round gland that encircles the urethra, 30% of semen is produced here, and secretions contain seminalplasmin which is an antibiotic to prevent urniary tract infections
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bulbo-urethra glands
located at base of penis, inurogenital diaphragm, secrete a thick alkaline mucus that helps with 2 things: neutralize any urinary acids and lubricates urethra and glans penis
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Penis
glans - expanded distal end, prepuce - foreskin, body or shaft - three columns of erectile tissue
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Shaft of Penis
erctile tissue consists of a complex 3D maze of blood vessels separated into channels, parasympathetic NS stimulates neurons to release nitric oxide and relaxes smooth muscle to increase blood flow (engorge with blood and now erect)
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copora cavernosa
two superior columns of erectile tissue w/ central artery
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copora spongiousm
chamber that surrounds urethra, contains small arteries
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Semen Contents: spermatozoa
normal sperm count is 20-100 million
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Semen Contents: seminal fluid
mostly from seminal vesicles (60%) and prostate (25%),
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Semen Contents: enzymes
function as antibiotics or to dissolve the mucus of the vagina, or to coagulate sperm
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Peristalsis control of penis
Sympathetic nervous system controls contractions of the vas defernes, spinal vesicles, and prostate. This causes the discharge of semen into the ejaculatory duct, and once bulbospongious muscle contracts we have ejaculation
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Endocrinology of male reprodcution
Hypothalamus releases gonadotropin which releases hormones (GnRH) across hyoiohyseal portal system which causes FSH/LH secretion by anterior pituitary gland
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Anterior Pituitary Gland
secretes gonadotropins, includinging FSH and LH
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FSH
follicle stimulating hormone - stimulates sperm production mainly by stimulating the susternacular cells
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LH
luteining hormone - stimulates testosterone secretion by the interstitial cells
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Testes
interstitial cells (Leydig cells) secrete mainly testosterone but also: responsible for development and maintenance of male secondary sexual characteristics, stimulates sperm production, increase libido, are inactive until activated by the gonadotropins at puberty, and high T levels give negative feedback on GnRH levels
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Reproductive cancer in males
Prostate cancer - most common, Testicular - one of the most curable forms of cancer, Breast - 1% of males and due to cancer in the ducts.
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Ovaries
lumpy, almond shaped organs near the lateral walls of the pelvic cavity, enclosed within extensive mesentery called broad ligament, have 3 major functions
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3 major functions of ovaries
production of immature oocytes, secretion of sex hormones like estrogen and progesterone, and secretion of inhibit (hormone that inhibits FSH levels.
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Oogenesis
forming a ova (egg) before birth oogonia (female stem cells) divide via mitosis to produce daughter cells called primary oocytes (46 chromosomes). btwn 3rd and 7th months of fetal development meiosis of primary oocytes begins but is suspended until puberty.
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Difference in males and females with mitosis
part of spermatogenesis in males throughout life, by females are done with it before birth
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If egg is fertilized the ovum finishes what?
meiosis II, duplicate chromatids separate in anaphase II, end result is one large ovum (23 chromosomes) and 2-3 nonfunctional polar bodies.
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How many eggs per life and what type?
500 total eggs per life are released, but over 10 million genetically different eggs are created.
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2 key differences in meiosis of ovaries vs testes.
cytoplasm of primary oocyte is unevenly distributed during two meiotic divisions so oogenesis produces 1 ovum. and ovaries release secondary oocytes whereas testes release spermatozoa. Secondary oocyte only goes through meiosis if fertilized.
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Female Reproductive Tract: Uterine tubes
(fallopian) hollow and muscular runnings from ovaries to uterus, not physically connected to uterus, instead fimbrae drape over the ovaries. inner surface is lined with cilia to help draw secondary oocyte inward. Once oocyte enters, it moves via peristalsis (NS turns this on hours before ovulation, secondary oocyte must be fertilized w/in 12-24 hrs or will degenerate.)
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Uterine tube secretions
lipids and glycogen to be used by spermatozoa and developing fertilized egg
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Female Reproductive Tract: Uterus
functions for the developing embryo include: protection, nutritional support, and removal of waste. stabilized by ligaments, includes the Cervix (inferior part of uterus that protects the vagina.
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Female Reproductive Tract: Cervix
glands moisten the lining of the vagina, and cervical os which is the opening of the center of the cervix that dilates during labor.
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Female Reproductive Tract: Uterine wall
myometrium - thick, outer layer with 3 different types of smooth muscle that help push during labor. Endometrium - thin, inner lining with glands, vessels, and helps change estrogen levels
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Female Reproductive Tract: Vagina
muscular tube that runs btwn cervix and genetalia, wall has blood vessels and smooth muscle, lumen is lined with stratified squamous. Vestibular bulbs - erectile tissue on either side of the vaginal entrance.
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Bacteria of vagina
inhabit the vagina and feed on nutrients of cervical mucus, creates an acidic environment that limits pathogens and inhibits motility of sperm (reason for sperm to be alkaline)
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Female Reproductive Tract: Externa Genetalia
vestibule - central space surrounded by labia minora, greater vestibular glands - discharge into vestibule (same origin as bulb-urethral glands)
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Reproductive Cancers in femlaes
breast - most common other than skin cancer (2nd deadliest) Endometrial - most common in tract. Ovarian - most dangerous (1 in 70 chance of getting it and dangerous because hard to diagnose early). Cervical - most common and caused by HPV
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Ovarian cycle
monthly chain of event that lead to ovulation
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ovarian follicles
structures where oocytes grow and undergo meiosis...200,000 follicles by puberty
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Phases of ovarian cycle
follicular phase and luteal phase
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follicular phase
formation of primary follicles - begins with activation of 2 dozen primordial follicles, oocyte enlarges and cells become cuboidal, now called granulosa cells
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Granulosa cells
multiply tip the oocyte doubles in size and adds a get coating of glycoproteins called zone pellucida. Tough outer covering is the theca follicle and develops a richly vascularized smooth muscle and endocrine cells
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Tertiary follicles
follicle is huge at this point, can see bulge in ovary, contains antrum - central cavity filled with follicular fluid. Secondary oocyte drifts free within antrum and granulosa cells form protective layer called cornea radiata
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Luteal phase
corpus luteum: empty territory follicle transforms into an endocrine structure called the corpus luteum, this secretes mostly progesterone which prepares the uterus for pregnancy by stimulating the maturation of the uterine lining and the secretions of the uterine glands. Degernates unless fertilized.
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Development
conception occurs within uterine tubes a day after ovulation. Acrosomal cap of spermatozoa release enzymes so sperm can penetrate corona radiate and zone pellucida of secondary oocyte.
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Development of meiosis II
when sperm touches oocyte membrane it gets activated into meiosis II, divides into mature ovum and polar body. Polyspermy is prevented because ovum is depolarized and zone pellucida hardens. Zygote is the results (46 chrom and shared DNA)
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Cleavage
zygote undergoes series of mitotic cell divisions but no change in size,
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morula
stage in which preembyro is a solid ball - 3rd day
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blastocyst
hollow ball stage (day 5) the outer layer of cells become part of placenta and inner cell mass becomes embryo
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implantation
blastocyte burrows into the endometrium and the placenta begins to form (7 days after fertilization)
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human chorionic gonadotropin
hCG appears in mother and is signal of pregnancy if found in blood, like LH, it maintains the corpus luteum and promotes progesterone...thus menses does not normally occur and the endometrium continues to function.
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miscarriages
occur in 15% OF RECOGNIZED PREGNANCIES, mostly from developmental problems (chromosomal deficients) or hormonal problems
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Lactation
infant ingests colostrum for first 2-3 days which is protein rich milk, lots of anitobides as well for immunity.
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Composition of regular breast milk
mostly water, proteins and amino acids, lipids, sugars, salts, lysosomes (antibiotic enzyme), and mucins that can inhibit viruses.
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several hormones involved in development of mammary glands
prolactin and growth hormone, estrogen and progesterone from ovary thyroxine. occur in the subcutaneous fat of breast, layer of CT separates them from muscle, and divided into lobes which contain lobules.
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milk-let down reflex
infant sucks at nipple which stimulates receptors, sensory info to spinal cord and up to mothers hypothalamus, this stimulates posterior pituitary gland to release oxytocin, travels in the blood to mammary glands to release milk.
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FSH in females
stimulates growth of ovarian follicle and secretion of two hormones from ovaries, estradiol and inhibin.
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LH in females
sharp rise triggers ovulation, and stimulates formation of corpus luteum and thus secretion of progesterone
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Ovaries
estrogens responsible for development and maintenance, interact with progesterone to bring cyclic changes of the uterine lining and act on CNS to increase female libido.
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Progesterone
acts with estrogen to bring on menstral cycle, prepares uterus for pregnancy and prepares mammary glands for lactation.
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Ovaries are inactive until...
activated by FSH/LH at puberty
