The motor activity of the smooth muscle of the gut is controlled by the
The ___ ___ ___ primarily propels food
The enteric nervous system
The digestive tract is a long tube made up of 4 layers, name them.
- muscularis propria
Between 2 of digestive tract layers, there is a network of nerves that are the source of?
electrical excitation to make the smooth muscles contract
How many nerve plexuses are responsible for the innervation of the digestive system
The myenteric nerve plexus is responsible for?
The submucosal nerve plexus is responsible for? What else exhibits some sort of control over the digestive system?
- stimulating activity in the muscular layer
- gastric secretions
Slow waves are a type of _____ ____ with an intensity between __ & __
- graded potential
- 5mV and 15mV
Slow waves don't produce ____ but rather produce _____ ____ when they hit _____
- spike potentials
The ____ ____ stimulates the opening of Ca/Na channels. This leads to a ____.
- Spike potentials
It is thought that the cause of slow waves are ____ ___ of ___. Also state the function
- interstitial cells of cajal
- act as pacemakers for smooth muscle
In the female reproductive cycle, ___ is/ are normally produced every 28days.
A single ovum
______ release is stimulated by proteins, fats and acid
Cholecystokinin released by?
I cells of small intestine
- Stimulates: (I)pancreatic enzyme and bicarbonate release into the small intestine (II) gall bladder contraction
- Inhibits: (I)gastric emptying
A hormone that exerts control over the digestive system. Also state what stimulates the release of that hormone (3) (hint released by I cells)
Proteins, fats and acids
Cholecystokinin stimulates pancreas to release?
enzymes and bicarbonate
Spike potentials are ___ ____ that occur when resting potential reaches roughly ___
The greater ____ of slow wave, the greater the ____ of spike potentials generated
Depolarization of spike potentials occurs when?
Ca/Na channels open (long duration)
Spike potentials are the result of ____ ____ reaching a _____. Spike potentials cause Ca/Na channels to ____. Ca and Na flow in at a ____ rate.
- slow waves
In spike potentials, Ca influx triggers the release of more __ which causes a _____ of ____
- contraction of smooth muscle
Possible causes of physiological shock (4)
- Hypovolemia (low blood volume)
- hemorrhagic shock (bleeding out)
- cardiogenic shock (decrease in heart's ability to pump blood)
- decreased venous return/ decreased cardiac output
Cardiac abnormalities can decrease?
heart's ability to pump blood
Cardiogenic shock and decreased venous return/decreased cardiac output are both forms of physiological shock. Name 3 causes of cardiogenic shock and 3 factors that lead to decreased venous return/ decreased cardiac output
- Cardiogenic shock: (I)myocardial infraction (II) arrhythmia (III) severe valve dysfunction
- Decreased venous return/ decreased cardiac output: (I) diminished blood volume (hypovolemic shock) (II) decreased vascular tone (III) obstruction of blood flow
Follicle stimulating hormone (FSH) and testosterone stimulates the growth and development of sperm _____.
indirectly by binding to sertoli cells
The absence of _____ in the fetus will further the development of the ____ into the female reproductive tract.
mullerian inhiting substance; mullerian ducts
Which of the following ions acts as a buffer to minimize changes in intracellular pH?
Name two intracellular buffers
- Phosphate (MAJOR)
Contraction of mesangial cells results in a ____, which decreases glomerular filtration
Decreases surface area of capillaries available for filtration
Macrophages that phagocytose large quantities of lipids may develop into?
List 3 parts of plaque structure (atherosclerosis)
- foam cells
- smooth muscle cells
an accumulation of lipids, foam cells and SMCs in the tunica intima
a clump of cells that swells outwards into the lumen and starts to block the blood vessel itself and could eventually rupture. (early development is seen in fatty streaks which show up in blood vessels).
Chemical digestion refers to
modifying the chemical structure of food by enzymatic breakdown:
- carbs into simpler sugars
- proteins into peptides and amino acids
- lipids into fatty acids & glycerol
Chemical digestion is the enzymatic breakdown of molecules to convert them into?
- Useful source of energy or for other biochemical purposes
- **Enzymes chemically modify the composition of food
In the absence of the implantation of a fertilized embryo, the menstrual phase of the uterine cycle is initiated by the degeneration of the ___ ___
When is the second polar body produced?
Following meiosis II in females
Where does blood leaving the glomerulus go to next?
Most of the carbon dioxide in the blood is transported as
Bicarbonate ions in the blood
which of the following is an accessory organ of digestion?
What hormone is responsible for secondary sex characteristics in males
Sex differentiation of a fetus is controlled by the production of ____, which is coded for by the _____ gene
Testis-determining factor (TDF); sex-determining region Y (SRY) P. 705
In tubuloglomerular feedback, an increase in glomerular filtration rate would increase the ____, thereby stimulating the release of a paracrine factor from the macula densa that would _____.
Flow of tubular fluid; constrict the afferent arteriole
As the food is broken down into smaller pieces in the mouth, it is combined with _____ that facilitates its movement down the esophagus.
Saliva lubricates the food particles making it easier to _____ them. It also contains _____.
What the function of amylase in saliva
begins the digestions of complex carbs into simpler carbs and sugars
Prolonged vomiting of the stomach's contents can result in
High carbon dioxide concentration in body fluids is called
Mechanical digestion refers to
- Breakdown of large particles of food into smaller particles so they are easy to swallow
- increases the surface area to breakdown more nutrients
The absorption of nutrients in the GI tract occurs primarily in the? What role do villi play?
- small intestine
- villi increase surface area and microvilli (surface with brush border enzymes)
During absorption of nutrients in the GI tract, nutrient rich blood goes where?
Liver for glycogen storage
Where does fertilization usually occur?
How does severe vomiting cause a metabolic alkalosis
loss of acids
In the digestive system, HCl is released by _____, whereas HCO3- is secreted primarily from the _____.
Parietal cells of stomach; Pancreas
Gastrin release is stimulated by? (3)
- stomach and small intestine distention/ eating food
- vagal nerve activity
What inhibits gastrin?
What produces gastrin?
- presence of acids
- G cells in stomach wall
What does gastrin stimulate
gastric acid secretion
Slow waves are
- Rhythmic; not action potentials
- They are graded potentials and DO NOT induce muscle contraction
Slow waves induce the appearance of intermittent ___ _____ which cause?
- spike potentials
- smooth muscle contraction
How many slow wave cycles occur in the stomach and small intestine per minute?
- Stomach: 3 per minute
- Small intestine: 12 per minute
- **duodenum: 11-12 per minute
- **ileum: 9 per minute
Slow waves are caused by ___ acting as ___
interstitial cells of Cajal acting as pacemaker cells for smooth muscle
Slow waves activate?
Atherosclerosis can happen in ___ &___; higher occurrences in ____.
What type of disease is atherosclerosis?
Inflammatory disease or Inflammatory vascular disorder
If the arterial bulge (_____) ruptures it will expose the contents of the underlying subendothelial layer like ____ & ___ _____ ____. What do they induce?
- collagen & von willebrand factor
- inducers of clotting factors, they make blood clots begin to form
What is the process of infection for atherosclerosis (-- means leads to) (15 steps)
Through Endothelial receptors, LDL is distributed across the sub-endothelial layer --LDL metabolizes cells it encounters/gets oxidized --cells release chemical attracting macrophages (cell adhesion molecules)--macrophages move into cell--macrophages break down oxidized LDL by scavenger receptor--phagocytosis turns macrophage into (yellow) foam cells--foam cell divides/releases cytokines that attract smooth muscle cells-- causing inflammation and forming a fatty streak-- atheroma forms and swells out--blocks vessel-- ruptures--collagen comes and clot forms--intrinsic pathway blockage--embolism--possible stroke or heart attack
fatty streaks are formed by
lipid-engorged macrophages (leading to an aggregation of SMCs & inflamed foam cells)
Risk factors that increase chances of atherosclerosis
- sedentary lifestyle
Isolated mutant gene without fatty streaks that can be used to treat atherosclerosis
The chloride shift occurs when?
Bicarb is dumped into blood stream in exchange for Cl- with H+ to form HCl
Purpose of chloride shift?
To keep red blood cell's voltage or membrane potential at the same charge. (-70mV)
Emulsification aids in the digestion of fats by _____.
Increasing the surface area of the fat globule exposed to enzymes
The ____ produces bile which is an ____. It helps fat mix with ____ by _____ the fat.
Emulsification breaks large fat globules into small fat globules what are two results?
- Increases the surface area of the fat
- Increases/ improves its digestion in the small intestine
Which is not a function of the kidneys?
Producing the hormones melatonin and oxytocin
Function of the kidneys: (9)
- secretion/ hormone production (like erythropoeitin & renin)
- regulates pH
- regulates blood pressure
- urine production
- indirect regulation of interstitial fluid
- endocrine function
- activation of vitamin D
G cells of the stomach secrete
7 expected factors of progressive hemorrhagic shock
- cardiac depression
- vasomotor failure
- blockage of very small vessels
- increased capillary permeability
- generalized cellular deterioration
- tissue necrosis in severe shock
- acidosis in shock
define cardiac depression and state results
When blood flow decreases below what is required to provide nutrients and oxygen adequately to heart
- Depressed cardiac output
- Decreased ATP
diminished blood flow to brain's vasomotor center depresses the center causing less activity and eventual shut down
During vasomotor failure, what causes vasodilation?
Decreased vascular tone
What causes blockage of very small vessels? State 2 results
Sluggish blood flow leads to clotting due to accumulation of carbonic acid, lactic acid and other products of ischemic tissues.
- Increased acidity
- Decreased pH leads to CNS depression
What leads to increased capillary permeability? What is the result?
- Capillary hypoxia
- Further reduction of blood volume as fluid accumulates in the tissues
Which pump is decreased during generalized cellular deterioration? What is the result?
- Na+/K+ pump
- Accumulation of Na+ & Cl- and a loss of K+ in the cell. The tissues then swell due to osmosis
What are the three other results of generalized cellular deterioration?
- Mitochondrial activity decreases (especially in liver)
- lysosomes begin to break down releasing hydrolases leading to further deterioration
- cellular metabolism decreases
Two things to expect during cellular deterioration because some tissues experience greater damage than others during shock due to smaller blood supplies
- Cells nearer to arterial capillaries have better blood flow than venous capillaries
- Lesions may develop in the liver, kidneys, heart and lungs
Acidosis in shock results from poor oxygen delivery to the tissues. What are 2 expectations?
- cells shift to anaerobic respiration, producing large amounts of lactic acid
- poor perfusion leads to impaired removal of CO2 as well, which also contributes to acidosis
The primary role of the carbonic acid-bicarbonate buffer system is
- Stabilize pH
- Limit pH changes caused by organic and fixed acids
How does the bicarbonate buffer system stabilize blood pH
takes up protons or releases them as conditions of the blood change
All of the following will normally be found in the filtrate except
Expected content of glomerular filtrate
The ____ is a significant site of absorption of water and electrolytes, but NOT of nutrients
All of the non nutritional remains of the digestive process enter the ____ ____, where the absorption of ____ and ____ takes place. The remaining material at this point is subject to _____ breakdown.
- large intestine
- water and electrolytes
decreased cardiac output with simultaneous drop in blood pressure
During what renal process are molecules selectively removed from the tubule lumen, moved into the interstitial space, and removed from the kidneys by the peritubular capillaries and the vasa recta?
What cells function to secrete hydrogen ions into the lumen of the stomach?
Parietal cells aka oxyntic cells aka delomorphous cells
The most important chemical regulator of respiration is
Some fats end up in the bloodstream, but they don't flow very well in the blood because?
Blood is a water based solution that is polar, and fats/lipids are non-polar and hydrophobic.
To transport lipids, the ____ produces apo-lipoproteins that bind to the _____ thereby making transport possible.
When lipids are being transported, they bind to ___ receptors and will be taken into the ______ layer
- LDL receptors
- subendothelial layer
Lipids accumulate in the intimal layer and become _____. _____ processes cause surrounding cells to start releasing chemicals whose function is to?
- attract white blood cells, specifically macrophages
Chemicals cause vascular endothelium to express ____ ____ molecules that cause macrophages to adhere to?
- cell adhesion molecules
- wall of vessel and move in
Macrophages consume the _____ lipids. Foam cells begin to secrete various chemicals that stimulate?
- smooth muscles to come into the area and start to divide in the in the intimal layer.
SMCs (smooth muscle cells) accumulate around foam cells and form _____, which will lead to the formation of a/an _____.
The force for glomerular filtration is the?
Blood pressure/hydrostatic pressure in glomerular capillaries
The loss of reproductive capacity that occurs as females age is caused by?
Changes in hormone secretory patterns: Less estrogen and progesterone
Chief cells aka _____ cells
Zymogenic or peptic cells
Once _____ mixes with HCl, it is converted into its active form ____.
Pepsin begins the chemical breakdown of?
protein into peptides
How does severe diarrhea cause metabolic acidosis?
Bicarbonate is unable to be absorbed by large intestine; lower GI accumulates a lot of bicarbonate
The hormonal trigger for menstruation involves a ____.
Loss of progesterone secretion from the corpus luteum
Areas where laminar flow is disrupted
- Branching points of arteries (i.e. brain, coronary, carotid)
- High risk areas for blood clots to form
What percentage of people who develop cardiogenic shock do not survive?
Nutrient absorption occurs primarily in the
As food is chemically digested, it is also absorbed through the ____ ____. The small intestine has ____ that contain blood vessels. The nutrients move through the ____ ___ and into the _____ ____ to be carried to the body's cells.
- intestine walls
- mucosal layer
- blood vessels
What stimulates release of secretin and what is it eventually released by?
- Release stimulated by acid and fat
- released by S cells in the small intestine
What does secretin secrete/release?
What does it inhibit?
- Secretes pepsin and releases pancreatic bicarbonate
- Inhibits gastric acid secretion
A hormone that exhibits some sort of control over the digestive system
What does luteinizing hormone (LH) cause in males?
Stimulates release/ production of testosterone by leydig cells
During myogenic regulation of glomerular filtration rate, an increase in mean arterial pressure will _____
cause the afferent arterioles to constrict and thereby maintain a relatively constant glomerular filtration pressure
Symptoms of low plasma pH may include:
- CNS depression
- Generalized weakness
- Deranged CNS function
- Severe: disorientation, coma or death
Once the chyme begins to enter the duodenum, it must first be _____ before any of the enzymes in the pancreatic juices can be activated.
Neutralized or deacidified
The pancreas secretes ______ in order to neutralize the very acidic chyme
When a B cell contacts a foreign or abnormal antigen, it develops into a ________ that releases________.
The body's nonspecific defenses against pathogens
- natural killer cells
- complement system
Which is NOT one of the body's nonspecific defenses against pathogens?
cytotoxic T cell
In the end, the complement system destroys invading bacteria by ________.
forming a membrane attack complex
Why is a secondary immune response stronger?
Memory cells produced during the primary response lead to a rapid proliferation of effector cells on subsequent exposure to the antigen.
Activation of a B cell by an antigen results in its proliferation and differentiation into ________,which secrete the antibodies that attack the antigen.
The ________ protein on the cytotoxic T cell binds to the ________ major histocompatibility(MHC) molecule on the infected cell.