Module 5 - Muscles & Digestive system Flashcards
4 functions of muscles
Produce movement, maintain posture, stabilise joints, generate heat
4 characteristics of muscles cell
Excitability, contractibility, extensibility, elasticity
3 types of muscles in the body
Smooth, cardiac and skeletal
What do skeletal muscles do
Attach to skeleton to produce motion
Six functions of skeletal muscle tissue
Produce skeletal movement, maintain posture and body position, support soft tissues, guard entrances and exits, maintain body temperate, store nutrients reserves
What do origin and insertion mean
Muscles have a fixed point of attachment (origin) and one moving point of attachment (insertion)
What’s a agonist do
Produces a particular movement
What does an antagonist do
Opposes movement of particular agonist
What does a synergist do
A smaller muscle that assists a larger agonist and helps stabilise origin of agonist
Agonists and antagonists ….
Work in pairs, when one contracts the other stretches
Anconeus
Elbow
Auricularis
Auricle of ear
Brachial is
Bra him
Capitis
Head
Carpi
Wrist
Cervicis
Neck
Externus
Superficial
Extrinsic
Outside
Inferioris
Inferior
Internus
Deep, internal
Intrinsic
Inside
Lateralis
Lateral
Medialis / medius
Medial, middle
Three layers of muscle tissue
Epimysium, perimysium, endomysium
Epimysium surround …
Each individual muscle cell
Perimysium surround
each bundle of muscle of cells called a fascicle
Endomysium surrounds
Each muscle
Function of epimysium
Separates muscle from surrounding tissue
What is the epimysium
The exterior collagen Layer that’s connected to deep fascia
What does the perimysium
Contains blood vessel and nerve supply to fascicles
What does the endomysium
Capillaries, nerve fibers and myosatellite cells (stem cells)
What is the sarcolemma
The cell membrane of a muscle fiber cell, surrounds the sarcoplasm
What are transverse tubules
Tubules that transmit action potential through cell
What do transverse tubules allow
Entire muscle fibers to contract simultaneously
What are myofibrils
Lengthwise subdivisions within muscle fiber
What are myofibrils made of
Bundles of protein filaments (myofilaments)
What are Thin filaments
Made of protein actin
What are thick filaments made of
Protein myosin
What is the membranous structure surrounding each myofibril called
Sacroplasmic reticulum
What are triads formed by
One tubules and two terminal cisternae
Function of cisternae
Release Ca^2+ into sacromeres to begin muscle contraction.
Between thick and thin filaments A band or I band
Thick filaments = A
Thin filament = I
Where is the m line
The centre of A band at the midline of the sarcomere
Where is the H band
The area around the M line has thick filaments but no thin filaments
Where are the Z lines
At the centre of the I bands
What are Titan
Are strands of protein that reach from tips of thick filaments to the Z line to stabilise the filaments
What do myosin heads do during contraction
Interact with actin filaments forming cross-bridges and pivot producing motion
What is the sliding filament theory
Thin filaments of sarcomere slide toward M line alongside thick filaments
Process of contraction
Neural stimulation of sarcolemma which causes excitation-contraction coupling where muscle fibers contract through interaction of Thick and thin filaments, tension is produced
What is the neuromuscular junction
Special intercellular connection between the nervous system and skeletal muscle fiber
What does the neuromuscular junction control
Controls calcium ion release into the sarcoplasm
What does contraction duration depend on
Duration of neural stimulus, number of free Ca2+ ions and the availability of ATP
What happens during muscle relaxation
Ca2+ conc drops, Ca2+ detaches from troponin actives sites are re-covered by tropomyosin
What is rigor Mortis
Fixed muscular contraction after death where ion pumps cease to function and calcium builds up in the sarcoplasm
What are motor units
Is in a skeletal muscle contain hundreds of muscle fibers that contract at the same time
What is isotonic contraction
Skeletal muscle changes length resulting in motion
What is isometric contraction
Skeletal muscle develops tension, but is prevented from changing Length
What is creatine phosphate
The storage molecules for excess ATP energy in resting muscles
What does creatine kinase do
Recharges ADP to ATP
What are the two ways do cells produce ATP
Aerobic metabolism of fatty acids in the mitochondria and anaerobic glycolysis in the cytoplasm
What is glycolysis
Primary source for energy source for peak muscular activity, produces 2 ATP per molecule of glucose, breaks down glucose from Glycogen stored in skeletal muscles
What is aerobic respiration
Primary energy source of resting muscles, breaks down fatty acids where 34 ATP are produced per glucose molecule
How is ATP generated during light activity
Anaerobic breakdown of carbohydrates, lipids or amino acids
How is energy provided during peak activity
Anaerobic reactions that generate lactic acid as a byproduct
What is anabolism
Use raw materials to synthesise essential compounds
What is catabolism
Process of Decomposing Substances to provide energy cells need to function
Two ingredients for catabolic reactions
Oxygen and organic molecules broken down by intracellular enzymes
What is the digestive tract
A muscular tune the extends from oral cavity to anus
Where does the digestive tract extend through from top to bottom
Pharynx, esophagus, stomach and small and large intestines
4 accessory organs of the digestive system
Salivary glands, liver, gallbladder and pancreas
Ingestion
Occurs when materials enter digestive tract via the mouth
What is mechanical processing
Crushing and shearing makes materials easier to propel along digestive tract
What is digestion
The chemical breakdown of food into small organic fragments for absorption by digestive epithelium
What is secretion
Release of water, acids, enzymes, buffers and salts by epithelium of digestive tract by glandular organs
What is absorption
Movement of organic substrates, electrolytes, vitamins and water across digestive epithelium into interstitial fluid of digestive tract
What is excretion
Removal of waste products from body fluids
What are the digestive organs and the peritoneum
Lined with serous membrane
What does the serous membrane contain
Superficial mesothelium, serosa, parietal peritoneum
Four major layers of the digestive tract
Mucosa, submucosa, muscularis externa, serosa
3 steps of peristaltic motion
Circular muscles contract behind bolus, longitudinal muscles ahead of bolus contract, wave of contraction in circular muscles
What is segmentation
Cycles of contraction that churn and fragment the bolus and mix contents with intestinal secretions
What are hormonal mechanisms
18 peptide hormone that affect most aspects of digestive functions
What are peptide hormones produced by
Enteroendorcine cells in digestive tract
4 functions of the oral cavity
Sensory analysis, mechanical processing, lubrication, limited digestion
4 functions of the tongue
Mechanical processing, manipulating to assist in chewing and prepare material for swallowing, sensory analysis and secretion of mucins and lingual lipase
Three pairs of salivary glands that secrete into oral cavity
Parotid salivary glands, sublingual salivary glands and submandibular salivary glands
4 functions of saliva
Lubricating the mouth, moistening and lubricating materials in the mouth, dissolving chemicals that stimulates taste buds, initiating digestion by salivary amylase
What is mastication
Also called chewing, food is forced from oral cavity to vestibule and back
What is the pharynx
A common passageway for solid food, liquids and air
Three regions of the pharynx
nasopharynx, oropharynx, laryngopharynx
What is the esophagus
A hollow muscular tube that conveys solid food and liquids to the stomach
Three layers of the esophagus
Mucosal, submucosal and muscularis
Three phases of deglutition (swallowing)
Buccal phase, pharyngeal phase, esophageal phase
4 major functions of the stomach
Storage of ingested food, mechanical breakdown of ingested food, disruption of chemical bonds in food, production of intrinsic factor
Where are gastric glands
In fundus and body of stomach
What are pyloric glands
Glands located in the pylorus, produce mucous secretion
What do g cells In the pyloric glands produce
Gastrin
What do d cells In the pyloric glands produce
Somatostatin
Three phases of gastric control
Cephalic, gastric and intestinal
What is the production of acid and enzymes by the gastric mucosa controlled by
CNS
What two things regulate the production of acid and enzymes by the gastric mucosa
Short reflexes of ENS and hormones of digestive tract
What happens during digestion and absorption in the stomach
Stomach contents become more fluid, pH approaches 2.0, pepsin activity increases and protein disassembly
Functions of the small intestine
Plays a role in digestion and absorption of nutrients (90% of nutrient absorption)
What is the duodenum
The segment of small intestine closest to the stomach
Functions of the duodenum
Receive chyme from the stomach and neutralise acids before they can damage the absorptive surfaces of the small intestine
What is the jejunum
The middle segment of small intestine
What occurs at the jejunum
Chemical digestion and nutrient absorption
What is the Ileum
The final segment of the small intestine that ends at the ilececal valve
What is the ileocecal valve
A sphincter that controls flow of material from the ileum into the cecum of the large intestine
What are plicae circulares
Permanent Transverse folds in intestinal lining
What are intestinal villi
A series of finger like projections in mucosa of small intestines
What are intestinal glands
Mucous cells between columnar epithelial cells
What’s the function of intestinal glands
Eject mucins onto intestinal surfaces
What are brush border enzymes
Intergral membrane proteins on the surfaces of microvilli that break down materials in contact with brush border
What is enteropeptidase
A brush border enzyme that activates pancreatic proenzyme trypsinogen
What are enteroendocrine cells
Produce intestinal hormones such as gastric, cholecystokinin and secretin
What are intestinal secretions
Watery intestinal juice, moisten chyme ,assist in buffering acids and keep digestive enzymes and products of digestion in solution
What is the function of gastrin
Promotes increased stomach motility and stimulates acids and enzyme production
When is secretin released
When chyme arrives in duodenum
Function of secretin
Increases secretion of bile and buffers by liver and pancreas
When is gastric inhibitory peptide
Secreted when fats and carbohydrates enter small intestine
Functions of cholecystokinin
Accelerates pancreatic production and secretion of digestive enzymes,
Cholecystokinin releases …
Hepatopancreatic sphincter and gallbladder
Function of vasoactive intestinal peptide
Stimulates secretion of intestinal glands, dilates regional capillaries, inhibits acid production in stomach
Function of enterocrinin
Stimulates mucin production by submucosal glands of duodenum
Shape of the large intestine
Horse shoe
Where does the large intestine extended from and to
Ileum to anus
4 functions of the large intestine
Reabsorption of water, compaction of intestinal Contents into feces, absorption of important vitamins produced by bacteria, storage of fecal matter
4 parts of the large intestine from start to finish
Cecum, colon, appendix and rectum
Four regions of the colon
Ascending colon, transverse, descending and sigmoid
What is the anal canal and what does it contain
Last portion of the rectum, contains small longitudinal folds called anal columns
What is the internal anal sphincter
A circular muscle layer of muscularis externa
What is the external anal sphincter
Encircle distal portion of anal canal, is a ring of a skeletal muscle fibers under voluntary control
What two things are reabsorbed in the large intestine
Water and bile salts
What two things are absorbed in the large intestine
Vitamins and organic waste
Three vitamins produced in the large intestine
Vitamin K, Biotin, Vitamin B5
What are indole and skatole
Nitrogen compounds responsible for odour of faeces
What do digestive enzymes do
Break molecular bonds in large organic molecules in hydrolysis
Three things brush border enzymes break things into
Sugars, phosphates and nitrogenous bases
What do lobules of the pancreas contain
Contain blood vessels and tributaries of pancreatic
What is pancreatic alpha-amylase
Carbohydrase that breaks down starches
What’s pancreatic lipase do
Breaks down complex lipids
What liver lobules
Basic functional units of the liver
Function of hepatocytes
Adjust circulating levels of nutrients through selective absorption and secretion
Function of hepatocytes
Absorb solutes from plasma and secrete materials such as plasma proteins
Describe the bile duct system
Liver secretes bile fluid into a network of narrow channels (bile canaliculi) between opposing membranes of adjacent liver cells
Function of the right and left hepatic ducts
Collect bile from all bile ducts of liver lobes
Where does the common bile duct empty into
Duodenal ampulla
Where does the cystic duct lead to
Gallbladder
What forms the common bile duct
Cystic duct and common hepatic duct
Where does blood leaving absorptive surfaces of digestive tract enter
Hepatic portal system and flows into the liver
Function of liver cells
Extract nutrients or toxins from the blood before they reach systemic circulation through hepatic veins
What does the liver do to excess nutrients
Removes and/or stores them
Function of bile
Emulsification where bile salts break lipid droplets apart
Function of the gallbladder
Stores and concentrates bile prior to excretion into small intestine
Function and location of the cystic duct
Extends from gallbladder, forms union with common hepatic duct forms common bile duct
What is cholecystokinin
Intestinal hormone that causes gallbladder to release bile into duodenum
Six stages of the digestive process
- Ingestion
- Propulsion (swallowing & peristalsis)
- Mechanical Digestion
- Chemical Digestion
- Absorption
- Defecation
What does propulsion
Swallowing & Peristalsis
What does mechanical digestion involve
Chewing, mixing with salvia, churning in stomach mixing food and digestive enzyme
What is chemical digestion
Hydrolyses complex food molecules into monomers via enzymes
Function of mucosal barrier
Prevents stomach from digesting itself
3 phases of regulation for gastric secretion
Cephalic, Gastric, Intestinal
Entero-endocrine cells
Secrete secretin, CCK
Function of paneth cells
secrete lysozymes
Whats absorbed in the large intestine
Water and electrolytes
Hydrolysis of sucrose formula
C12H22O11 + H2O -> C6H12O6 + C6H12O6
What do things that hydrolyse carbohydrates end in
-ase
What do things that hydrolyse proteins end in
- peptidase
What are nucleic acids hydrolysed by
pancreatic nucleases and brush border enzymes
what does amylase digest
carbohydrates
what does lipase digest
fats and oils
what does nuclease digest
nucleic acids
what does CCK stand for
cholecystokinin
Function of the liver
Filters monosaccharides and amino acids
functional unit of the liver
hepatocytes
Hepatocytes bile process
Secrete bile into canliculi which drain into bile ducts which drain into the common hepatic duct which joins with cystic duct to become bile duct
Two blood suppplies for lobule
1) Hepatic artery
2) Hepatic portal vein
Hepatic artery vs hepatic portal vein
artery carries oxygenated blood, vein deoxygenated blood with nutrients absorbed from digestive tract
How does blood from hepatic artery and vein enter liver
via the portal arteriole and portal venule respectively
What is the function of the liver if blood glucose is low
Glycogen stored in liver is converted to glucose and released to the blood (Glycogenolysis), gluconeogenesis, other sugars also converted to glucose
what is gluconeogenesis
conversion of non-carbohydrate molecules to glucose
Function of the liver if blood glucose is high
Glucose is converted to glycogen and triglyerides & stored in liver and adipose tissue
Process of bilirubin excretion in liver
Bilirubin -> urobilinogen (by bacteria in the gut) -> urobilin and stercobilin (a yellow brown pigment)
Function of kupffer cells
remove bacteria originating from intestines and worn out RBC and WBC
What is lactic acid produced by
Anaerobic muscle metabolism of pyruvic acid
What is hepatitis
Inflammatory disease of liver
What is cirrhosis
Prolonged inflammation due to chronic alcoholism
Function of gall bladder
Store and concentrates biles
What is the main function of the vagus nerve
Primary pathway for parasympathetic NS communication to and from the brain
Absorption of monosaccharides process
Transported into epithelial cell by protein carriers and then by facilitated diffusion into capillary blood
How is vitamin B absorbed
Involves intrinsic factor being secreted by the stomach
What transport is used for absorption of minerals
Active transport
