Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
51 Cards in this Set
- Front
- Back
|
Inspiration
|
The period when air flows into the lungs. The inspiratory center spontaneously controls the diaphragm and intercostal muscles responsible for inspiration.
|
|
|
Expiration
|
The period when gases exit the lungs. It depends more on lung elasticity than on muscle contraction. The oxygen enters and carbon dioxide leaves the blood in the lungs.
|
|
|
Where is the inspiratory and expiratory located?
|
In the MEDULLA OBLONGATA and PONS of the brainstem.
|
|
|
Sequence of events in Inspiration
|
1. Inspiratory muscle contract (diaphragm descends; rib cage rises)
|
|
|
2. Thoracic cavity volume increases
|
3. Lungs stretched; intrapulmonary volume increases
|
|
|
4. Intrapulmonary pressure drops to (-1mmHg)
|
5. Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 1 (equal to atmospheric pressure)
|
|
|
Sequence of events in Expiration
|
1. Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages)
|
|
|
2. Thoracic cavity volume decreases
|
3. Elastic lungs recoil passively; intrapulmonary volume decreases
|
|
|
4. Intrapulmonary pressure rises (+1mmHg)
|
5. Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0
|
|
|
What is surfactant?
|
A detergent like complex of lipids and proteins produced by the type II alveolar cells. The Surfactant decreases the cohesiveness of water molecules, much the way a laundry detergent reduces the attraction of water for water, allowing water to interact with and pass through fabric.
|
|
|
Within the medulla, a paired group of neurons known as the inspiratory center, or the dorsal respiratory group, sets the basic rhythm by automatically initiating inspiration.
|
Factors influencing ventilation?
|
|
|
Lung hyperinflation: Stretch receptors in the visceral pleura and large airways send inhibitory signals to the inspiratory center during very deep inspirations, protecting against excessive stretching of the lungs. This is known as the inflation, or Hering-Breuer, reflex.
|
Voluntary control: By sending signals from the cerebral cortex to the respiratory muscles, we can voluntarily change our breathing rate and depth when holding our breath, speaking, or singing. However, chemoreceptor input to the respiratory centers will eventually override conscious control and force you to breathe.
|
|
|
Pain and emotions: Pain and strong emotions, such as fear and anxiety, act by way of the hypothalamus to stimulate or inhibit the respiratory centers. Laughing and crying also significantly alter ventilation.
|
Pulmonary irritants: Dust, smoke, noxious fumes, excess mucus and other irritants stimulate receptors in the airways. This initiates protective reflexes, such as coughing and sneezing, which forcibly remove the irritants from the airway.
|
|
|
What is the normal value of tidal volume (TV)?
|
M and F=500 ml. It is the amount of air inhaled or exhaled with each breath under resting conditions.
|
|
|
What is inspiratory reserve volume (IRV)?
|
M=3100 ml F=1900 The amount of air that can be forcefully inhaled after a normal tidal volume inhalation.
|
|
|
What is expiratory reserve (ERV)?
|
M=1200 ml F=700 ml The amount of air that can be forcefully exhaled after a normal tidal volume exhalation.
|
|
|
What is Residual volume (RV)?
|
M=1200 ml and F=1100 ml The amount of air remaining in lungs after a forced exhalation.
|
|
|
What forces derives filtration at the glomerulus?
|
Glomerulus is like a ball of yarn. Blood enters each glomerulus via an afferent arteriole. Urine formation begins at the renal corpuscle as blood pressure forces fluid from the blood in the glomerulus through fenestrated capillaries into the capsular space. This movement of water and molecules (generally smaller than proteins) from the blood into the nephron is called
|
|
|
What isa the normal net filtration pressure and the normal blood pressure in the glomerulus?
|
The blood pressure in the glomerulus (~55 mm Hg) is much higher than the pressure in other capillaries of the body (<18 mm Hg). Furthermore, the capillaries of the glomerulus are much more permeable to water and solutes than most other capillaries in the body.
|
|
|
What percent of the filtrate is reabsorbed in the proximal tubule?
|
Reabsorbs all of glucose, lactate, and amino acids in the filtrate and 65% of the Na+ and water. Additionally, 90% of the filtrated bicarbonate, 60% of Cl-, and 55% OF k+.
|
|
|
What is the role of proximal convoluted tubule?
|
The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman's capsule to the loop of Henle. It sodium brings ions, organic molecules, vitamins and water into the epithelial cells, which is then pumped by Na/K ATPase into the interstitial space, which then flows into the blood.
|
|
|
What is the role of distal convoluted tubule?
|
The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting duct system. It is partly responsible for the regulation of potassium, sodium, calcium, and pH. It is the primary site for the kidneys' hormone based regulation of calcium (Ca).
|
|
|
What is the role of loop of henle?
|
In the kidney, the loop of Henle (or Henle's loop or ansa nephroni) is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. the loop of Henle's main function is to create a concentration gradient in the medulla of the kidney.
|
|
|
the loop of Henle creates an area of high urine concentration deep in the medulla, near the collecting duct. Water present in the filtrate in the collecting duct flows through aquaporin
|
channels out of the collecting duct, moving passively down its concentration gradient. This process reabsorbs water and creates a concentrated urine for excretion.
|
|
|
What is the percentage of water in the urine?
|
Urine is 95 percent water. The other five percent of our urine is made of dissolved and suspended solids, none of which are toxic.
|
|
|
what is nephron?
|
Nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.
|
|
|
A nephron eliminates wastes from the body, regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH.
|
Its functions are vital to life and are regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone. In humans, a normal kidney contains 800,000 to 1.5 million nephrons.
|
|
|
What is the function of salivary gland?
|
1. cleanses the mouth 2. dissolves food chemicals so that they can be tasted 3. moistens food and aids in compacting it into a bolus 4 contains enzymes that begin the chemical breakdown of starchy foods
|
|
|
what is the function of esophagus?
|
It carries food and does not involve in food propulsion. After the food is moves through the laryngopharynx, it is routed into the esophagus posteriorly as the epiglottis closes off the larynx to food entry.
|
|
|
what is the function of liver?
|
1. process the bloodborne nutrients in various ways- store glucose as glycogen and use amino acids to make plasma protein, 2. store fat soluble vitamins 3. play important role in deoxification such as ridding the blood of ammonia by converting it to urea.
|
|
|
What is the function of epithelial goblet cells?
|
Goblet cells are glandular simple columnar epithelial cells whose sole function is to secrete mucin, which dissolves in water to form mucus.
|
|
|
The talent of goblet cells is to secrete mucus, a viscous fluid composed primarily of highly glycosylated proteins called mucins suspended in a solution of electrolytes.
|
Mucus serves many functions, including protection against shear stress and chemical damage, and, especially in the respiratory tree, trapping and elimination of particulate matter and microorganisms.
|
|
|
What kind of epithelium is the anus lining?
|
The anal canal is divided into two unequal sections, upper and lower.
|
|
|
The upper 2/3 has longitudinal folds or elevations of tunica mucosa. Its mucosa is lined by simple columnar epithelium. Its lower ends are joined together by folds of mucus membrane called anal valves.
|
The lower 1/3 of the anal canal is lined by stratified squamous epithelium that blends with the skin. The lower third of the anal canal is supplied by the inferior rectal artery which is a branch of the internal pudendal artery.
|
|
|
What is the main digestive producing organ?
|
Small intestines is the organ where most of the digestion takes place. It is where much of the digestion and absorption of food takes place. . The primary function of the small intestine is the absorption of nutrients and minerals found in food. aka main gut
|
|
|
which nerve triggers the response during the cephalic phase of digestion?
|
The sight and thought of food, stimulation of taste and smell receptors from the hypothalamus and medulla oblongata from the VAGUS NERVE to parasympathetic enteric ganglia.
|
|
|
Which receptors trigger the gastric phase of digestion?
|
The stomach distension activates stretch receptors and initiates both myenteric reflexes and the long vagovagal reflexes.
|
|
|
What are the long reflex?
|
Long reflexes to the digestive system involve a sensory neuron sending information to the brain, which integrates the signal and then sends messages to the digestive system. While in some situations, the sensory information comes from the GI tract itself; in others, information is received from sources other than the GI tract.
|
|
|
When the latter situation occurs, these reflexes are called feedforward reflexes. This type of reflex includes reactions to food or danger triggering effects in the GI tract. Emotional responses can also trigger GI response such as the butterflies in the stomach feeling when nervous. The feedforward and emotional reflexes of the GI tract are considered cephalic reflexes.
|
What is short reflex?
|
|
|
Control of the digestive system is also maintained by ENS, which can be thought of as a digestive brain that can help to regulate motility, secretion and growth. Sensory information from the digestive system can be received, integrated and acted upon by the enteric system alone. When this occurs, the reflex is called a short reflex.
|
Although this may be the case in several situations, the ENS can also work in conjunction with the CNS; vagal afferents from the viscera are received by the medulla, efferents are effected by the vagus nerve. When this occurs, the reflex is called vagovagal reflex. The Myenteric plexus and Submucosal plexus are both located in the gut wall and receive sensory signals from the lumen of the gut or the CNS
|
|
|
Which nuerotransmitter stimulates smooth muscle contraction in the digestive tract?
|
neurotransmitter: Ach stimulatory or excitatory on GI functions: stimulating smooth muscle contraction, increases intestinal secretions, increases release of enteric hormones, vasodilatator, and dilation of GI sphincters.
|
|
|
What cause pyloric sphincter to contract?
|
The main functions of the pylorus are to prevent intestinal contents from reentering the stomach when the small intestine contracts and to limit the passage of large food particles or undigested material into the intestine.
|
|
|
When the duodenum begins to fill, pressure increases and causes the pyloric sphincter to contract and close. Muscular contractions (peristaltic waves) in the duodenum then push food deeper into the intestine. Because the pyloric sphincter is relatively narrow, only small amounts of well-emulsified food can pass through it even while it is open
|
What slows intestinal motility?
|
|
|
what stimulates motility of the intestine?
|
The stimulation for these contractions likely originates in modified smooth muscle cells called interstitial cells of Cajal. These cells cause spontaneous cycles of slow wave potentials that can cause action potentials in smooth muscle cells. They are associated with the contractile smooth muscle via gap junctions.
|
|
|
what is ingestion?
|
Is simply taking food into the digestive tract, usually via the mouth.
|
|
|
What is digestion?
|
Chemical or mechanical process of breaking down food stuffs to substances that can be absorbed.
|
|
|
What regulates the frequency of peristaltic contraction?
|
The frequency of peristaltic contractions is regulated by the interaction between pacemaker cells and smooth muscle cells
|
|
|
what are the normal peristaltic contraction of the stomach?
|
Peristaltic contractions of the stomach (~ 3-5/min) mix the stomach contents with gastric juice and empty the chyme into the duodenum
|
|
|
What slows gastric emptying?
|
The rate of gastric emptying is slowed by the presence of fats, acids, and hypertonic solutions in the duodenum; distention of the duodenum also slows the rate of gastric emptying
|
|
|
Which hormone regulates the gastric phase of digestion?
|
is in the stomach and stimulates the gastric glands to secrete pepsinogen (an inactive form of the enzyme pepsin) and hydrochloric acid. Secretion of gastrin is stimulated by food arriving in stomach. The secretion is inhibited by low pH .
|
|
|
Which organ of the digestive system does the most absorption of nutrients?
|
small intestine
|
