Systems Flashcards
3 layers of skin
epidermis, dermis and hypodermis
Corpuscles
Cutaneous sensory receptors. Receive stimuli when you are touched
What percentage of blood volume is retained in your skin
5%
Two types of perspiration
Insensible (unnoticeable) and sensible (noticeable)
Cyanosis
Blue skin (heart failure, poor circulation, severe respiratory issues)
Jaundice
Yellow skin (liver disorder)
Erythema
Red skin (fever, inflammation, allergy)
5 types of sweat glands
Eccrine (palms, forehead and feet soles), Apocrine (armpits and groin), Mammary (secret milk), Ceruminous (earwax) and sebaceous (oil glands)
6 stages of digestion
Ingestion, Propulsion, Mechanical Breakdown, Chemical Digestion, Absorption and Defection
Macromolecules
lipids, carbs, proteins and nucleic acids
Alimentary canal
gastrointestinal tract
Why do the mouth, esophagus and anus all contain simple squamous tissue?
to prevent abrasive action of chewing certain foods
Why do the stomach and organs below contain columnar cells?
They secrete mucus which protects your cells from being digestive
Peristalsis
Muscles take turns relaxing and contracting to move food down
Gastric phase
as stomach is distended from food, activates stretch receptors which stimulate medulla and turn pH of stomach up
Intestinal phase
sows rate at which food is emptied from stomach
Mastication
to chew
Names of jawbones
Maxilla and mandible
Names of muscles attached to jawbones
Buccinator and masseter
Which enzyme do salivary glands produce and what does it do
Salivary amylase - starts digestion of starch
3 portions of teeth
Crown, root and neck
Names of two sets of teeth
deciduous and permanent
What is the pharynx
back of mouth
Esophagus
connects mouth to stomach. Upper sphincter contains skeletal muscles and lower sphincter contains smooth muscle
4 main regions of stomach
cardia, fundus, body and pylorus
What is between the pylorus and duodenum?
pyloric sphincter
What happens when the stomach is empty?
Mucosa lies in large folds called rugae
What does lingual lipase do?
digests triglycerides into fatty acids and diglycerides in the acids environment of stomach
How many layers of smooth muscle does the stomach wall consist of?
3
3 muscle groups
circular, longitudinal, oblique
3 parts of small intestine
Duodenum, jejunum and ileum
What does the small intestine do?
Its glands produce enzymes and mucus
the microvilli, villi and circular folds of its walls provide a large surface area for digestion and absorption
Main function of colon
absorption of water
Parts of the colon
Ascending, transverse, descending and sigmoid
Parts of the large intestine
Caecum, colon, rectum and anal canal
What does the large intestine do?
Absorbs water, ions and some vitamins
What stimulates the release of cholecystokinin?
Arrival of lipids in the duodenum
How are substances carried from the small intestine to the liver?
By the hepatic portal vein
What are parietal cells responsible for?
The production of the intrinsic factor (a glycoprotein)
What is the synthesis and storage of fat called?
lipogenesis
What does cholecystokinin do?
Stimulates the release of bile
Where is the pancreas?
lies behind the stomach
What does pancreatic juice contain?
enzymes and fluid
What is the pancreas made up of?
small clusters of glandular epithelial cells called acini which constitute the exocrine portion of the organ
Types of bile that emulsify fat
sodium taurocholate and sodium glycocholate
Cholecystectomy
removal of the gallbladder
Process of bile
made by liver, travels down hipatic duct, stored in gallbladder, travels down cystic duct, behind pancreas and then through duodenum
Components of bile
Hepatocytes, bile canaliculi, hepatic sinusoids, central vein and hipatic veins
What do hepatocytes do?
release bile
What do hepatic sinusoids contain?
stellate reticuloendothelial cells
Functions of the liver
secrets bile, phagocytosis of bacteria, processing of drugs and hormones, carbohydrate, lipid and protein metabolism, excretion of bilirubin, storage of vits and minerals, activation of vitamin d
organs of the respiratory system
nose, pharynx, larynx, trachea, bronchi and lungs
Otorhinolaryngology
diagnosis and treatment of ears, nose and throat
3 types of respiration
pulmonary ventilation, external respiration and internal respiration
Conducting zone
consists of a series of interconnecting cavities and tubes both outside and within the lungs
Respiratory zone
consists of tissues within lungs where exchange occurs between air and blood
Average atmospheric pressure
760 mmHg
Sternocleidomastoid
muscles in neck
What do carotid arteries do?
feed blood to brain
Nose
contains nares which prevent how much dirt you breathe in. Green snot indicates infection
Pharynx
throat. passageway for air and food. wall is composed of skeletal muscle and lined with mucous membrane
Larynx
voice box. Contains thyroid cartilage, epiglottis, cricoid cartilage, arytenoid cartilage, false vocal cords and true vocal cords
How is pitch of voice controlled?
By tension of vocal cords. Swollen when you have a cold which is why voice is deeper.
Trachea into bronchi
Divides into left and right primary bronchus, which then divide to form the lobal, secondary bronchi, one for each lung lobe. Lobar bronchi branch to form segmental, tertiary bronchi which divide several times, forming bronchioles. These branch to form terminal bronchioles which then give alveoli.
How many lobes does each lung have?
Left has 2 and right has 3
Lungs
paired organs in thoracic cavity enclosed by pleural membrane.
Layers of pleural membrane
Parietal (outer) and visceral (inner)
What do lobules contain?
lymphatic vessels, arterioles, venules, terminla bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli
What is the structure of alveoli?
racemose structure
When do we inhale and exhale?
Inhale when pressure in lungs is lower than atmospheric pressure and exhale when pressure in lungs is higher
Diaphragm
contracts when it receives nerve impulses from phrenic nerves
Minute ventilation
total volume of air inhaled and exhaled each minute
Lung volumes
tidal, inspiratory reserve, expiratory reserve, residual
What does surfactant do?
prevents friction
Elastic recoil
our ability to automatically breathe out
Ventral repiratory group
controls voluntary forced exhalation, increases force of inspiration
Dorsal respiratory group
controls mostly inspiratory movements and their timings
Ventilatory rate
tightly controlled and determined by blood levels of CO2
What do chemoreceptors do?
detect changes in blood pH that require changes in involuntary respiration
Which centres of pons work together to control breathing?
Apresutic (stimulating) and pneumotaxic (limiting)
How does the medulla help with breathing?
sends signals to initiate inspiration and expiration
Lacteal
absorbs fats and fat soluble vitamins
Type l alveolar cell
branched cell with multiple cytoplasmic plate which represent gas exchange surface
Type ll alveolar cells
responds to damage of type l cells by dividing and differentiating into both type l and type ll cells. also synthesise, store and release surfactant into alveolar hypophase to optimise conditions for gas exchange
Effect of damage to type l alveolar cells
increase entry of fluid to alveoli and decreased clearance of fluid from alveolarspace
Effect of damage to type ll alveolar cells
decreased production of surfactant which can lead to alveolar collapse. Can lead to fibrosis.
Breathing problems as delivery of oxygen is impaired. Babies would have extreme difficulty breathing and would struggle to survive.
Partial pressure
Pressure of a specific gas in a mixture
External respiration (pulmonary gas exchange)
exchange of gases between alveolar air and pulmonary blood capillaries
Internal respiration (systemic gas exchange)
exchange of gases between systemic tissue capillaries and systemic tissue cells
How is oxygen transported round body?
98.5% of blood O2 is bound to haemoglobin in red blood cells. Association of O2 and haemoglobin is affected by PO2, pH, temperature and PCO2.
How is CO2 transported round body?
3 ways: 7% dissolved in plasma, 23% binds with globin of haemoglobin and 70% is converted to bicarbonate ions (HCO3-)
2 areas of respiratory centre
Medulla oblongata and pons varolii
What does the inspiratory area do?
sets basic rhythm of respiration
DRG
Dorsal Respiratory Group
How does active DRG work?
diaphragm contracts and external intercostal muscles contract during their most active phase which leads to normal quiet inhalation
How does inactive DRG work?
diaphragm relaxes and external intercostal muscles become less active and relax, followed by elastic recoil of lungs which leads to normal quiet exhalation
VRG
Ventral respiratory group
How do VRG cause forceful inhalation?
accessory muscles of inhalation (sternocleidomastoid, scalene and pactoralis minor muscles) contract
How do VRG cause forceful exhalation?
accessory muscles of exhalation (internal intercostal, external oblique, internal oblique, transversus abdominis and rectus abdominis muslces) contract
Pons
top of brain stem
Medulla
just below pons
What does a dissociation curve show?
plots proportion of haemoglobin in its oxygen saturated form, against the partial pressure of oxygen
What does a shift to left on dissociation curve show?
increase in pH, decrease in CO2, decreased temperature
What does a shift to right on dissociation curve show?
decrease O2 affinity of haemoglobin, increase in CO2, increased temperature
What will a lack of haemoglobin cause?
shortness of breath, ireegular heartbeat, chest pain
What will too much haemoglobin cause?
causes body to make too many red blood cells, causing blood to thicken, leading to clots, heart attacks and strokes
Cephalic phase
the smell, sight, sound or thought of food activates neural centres in the brain
Gastric phase
promotes gastric juice secretion and gastric motility. The pyloric sphincter relaxes, which promotes gastric emptying. Gastric motility and gastric secretion decrease in order to slow the exit of chyme from the stomach, which prevents the small intestine from being overloaded with more chyme than it can handle
Gastric motility
Contractions of gastric smooth muscle serves two basic functions: ingested food is crushed, ground and mixed, liquefying it to form what is called chyme. chyme is forced through the pyloric canal into the small intestine, a process called gastric emptying.
Intestinal phase
the activities that occur during the various phases of digestion are coordinated by hormones, secretion and cholecystokinin
What does cholecystokinin do in the intestinal phase?
opens the oddi sphincter to allow bile and digestive juices to flow between the pancreas and small intestine
Gastrin
stomach mucosa (pyloric region). The secretion of gastric juice increases motility and relaxes the pyloric sphincter
Secretin
intestinal mucosa. secretions from pancreas, stimulates secretion of digestive enzymes and gives the feeling of satiety
Satiety
feeling full
What happens immediately after a meal in the small intestine?
Segmenting contractions and pacemaker cells
Post absorptive state in small intestine
peristaltic contractions and successive waves are more distal
Protein digestion in duodenum
Trypsin and Chymotrypsin in pancreas, carboxypeptidase and aminopeptidases
Lipid digestion
emulsification by bile salts to form small droplets, then pancreatic lipase changes the lipids to monoglycerides or fatty acids, then go on to form micelles and simple diffusion through the plasma membrane
Lipid digestion inside epithelial cells
resynthesised to triglycerides, then coated by proteins to form chylomicrons. They leave the epithelial cells and enter the lymphatic capillaries, which are called lacteals. The lacteals merge to form larger lymphatic vessels that transport the chyle to the thoracic duct where it is emptied into the bloodstream at the subclavian vein.
Heart structure
located between lungs in thoracic cavity. The apex (pointed end) is formed by the tip of the left ventricle and rests of the diaphragm. The ease of the heart is opposite the apex and is formed by the atria, mostly the left atrium.
Pericardium
membrane that surrounds the heart and holds it in place. It consists of two parts: fibrous and serous.
Outer fibrous pericardium
a tough, irregular connective tissue layer. It prevents overstretching of the heart, provides protection and anchors the heart in place.
Potential problem with outer fibrous pericardium
doesnt stretch so if any inflammation or excess fluid, the excess pressure could constrict the heart and impair pumping.
Inner serous pericardium
a thinner membrane that forms a double layer around the heart
Outer parietal layer of serous pericardium
fused to the fibrous pericardium
Inner visceral layer of serous pericardium
adheres tightly to the surface of the heart
Pericarditis
inflammation of the pericardium, causing a sudden onset of chest pain. Could be due to a viral infection or TB
3 layers of heart wall
epicardium, myocardium and endocardium
Epicardium
external layer - thin, transparent outer layer of wall. Composed of mesothelium and connective tissue
Myocardium
middle layer - consists of cardiac muscle tissue, which constitutes the bulk of the heart
Cardiac muscle fibres
involuntary, striated and branched cells. Form 2 separate networks - one ventricular and one atrial
Cardiac muscle fibre connections with other fibres
each fibre connects with other fibres by thickenings of the sarcolemma called intercalated discs. Within the discs are gap junctions that allow action potentials to conduct from one cardiac muscle fibre to the next
Endocardium
thin layer of simple squamous epithelium that lines the inside of the myocardium and covers the valves of the heart and the tendons attached to the valves
Atria
two upper chambers of heart
Ventricles
two lower chambers of heart
Which ventricle is thicker and why?
left due to pressure - left ventricles delivers blood to more areas of the body
What separates the two atriums?
a thin partition called the interatrial septum, which has an oval depression called the fossa ovalis
What separates the two ventricles?
an interventricular septum
Superior vena cava
brings deoxygenated blood to the right atrium from parts of the body above the heart
Inferior vena cava
brings deoxygenated blood to the right atrium from parts of the body below the heart
Coronary sinus
drains deoxygenated blood from most of the vessels supplying the wall of the heart
Which ventricle contracts first?
they contract simultaneously
How does deoxygenated blood travel around the heart?
Right atrium receives deoxygenated blood from 3 veins and then delivers the blood to the right ventricles, which pumps it into the pulmonary trunk. The pulmonary trunk then divides into a right and left pulmonary artery, to the corresponding lung.
How does oxygenated blood travel around the heart?
Oxygenated blood enters the left atrium via four pulmonary veins. The blood then passes into the left ventricle, which pumps the blood into the ascending aorta. From here the oxygenated blood is carried to all parts of the body.
Ligamentum arteriosum
a small ligament that is the remnant of the ductus arteriosus formed within three weeks after birth. At the superior end, the ligamentum attaches to the aorta—at the final part of the aortic arch
Septal defects (holes in the heart)
heart starts as 1, breaks down into 4 parts soon after birth. A gap can form between the right and left atria.
How many valves does the heart have? Describe them
4 - made up of dense connective tissue covered by endothelium. They open and close in response to pressure changes as the heart contracts and relaxes
Atrioventricular (AV) valve
lies between the atria and ventricles. Tricuspid and bicuspid (mitral)
Tricuspid valve
AV valve between right atrium and right ventricle. Consists of three cusps
Bicuspid (mitral) valve
AV valve between left ventricle and left atrium. Has two cusps.
What must happen for blood to pass from an atrium to a ventricle?
an atrioventricular valve must open
Pulmonary valve
lies in the opening where the pulmonary trunk leaves the right ventricle
Aortic valve
at the opening between the left ventricle and aorta
What do valves prevent?
prevent blood flowing back to the heart
How do valves prevent blood from flowing backwards?
They consist of semilunar cusps which attach to the artery wall and permit blood to flow in one direction only
In which direction does blood flow through the heart?
From high to low pressure
How is movement of the blood through the heart controlled?
by the opening and closing of valves and the contraction and relaxation of the myocardium
Coronary circulation
the flow of blood through numerous vessels in the myocardium
Principal coronary vessels
the left and right coronary arteries, which originate as branches of ascending aorta. Each artery branches several times to deliver O2 and nutrients throughout the heart muscles
Coronary sinus
vein on posterior surface of heart and collects most deoxygenated blood and empties into the right atrium
SA
sinoatrial
AV
atrioventricular
SA node
located in the right atrial wall, begins cardiac excitation. natural pacemaker of heart
AV node
located in interatrial septum, just anterior to the opening of the coronary sinus. Action potential slows considerably, providing time for atria to empty blood into ventricles
Process of action potential
From AV node, action potential enters the AV bundle in the interventricular system. AV bundle is the only site where action potentials can conduct from atria to the ventricles. After conducting through AV bundle, the action potential enters both right and left bundle branches that course through the interventricular septum towards apex of heart. Finally, Purkinje fibers rapidly conduct the action potential, first to apex of ventricles and then upwards to the rest of the ventricular myocardium.
Action potential
brief change in voltage across cell membrane of heart cells. Caused by the movement of charged atoms between inside and outside of cell, through proteins called ion channels.
Electrocardiogram (ECG)
conduction of action potentials through heart generates electrical currents that can be picked up by electrodes placed on skin
P wave
small upward deflection on ECG. Represents atrial depolarisation, which causes contraction so the atria contracts after the P wave begins
QRS complex
begins as a downward deflection, then continues as a large, upright, triangular wave and ends as a downward wave. Represents the onset of ventricular depolarisation so ventricles contract.
T wave
dome shaped upward deflection that indicates ventricular repolarisation and occurs just before ventricles start to relax
Normal cardiac cycle
two atria contract while two ventricles relax and two ventricles contract while two atria relax
Systole
phase of contraction (top BP number)
Diastole
phase of relaxation (bottom BP number)
3 phases of cardiac cyle
relaxation period, atrial systole, ventricular systole
Relaxation period of cardiac cycle
begins at end of cardiac cycle when ventricles start to relax and all 4 chambers are in diastole
Heart sounds
First sound, lubb, comes from AV valves closing after ventricular systole begins. Second sound, dupp, is from semilunar valves closing at end of ventricular systole.
Functions of blood
transportation, regulation and protection
What does the blood transport?
O2, CO2, nutrients, hormones, heat and waves
What does the blood regulate?
pH, body temperature, water content of cells
What does the blood protect?
against blood loss through clotting, against disease through phagocytic white blood cells and proteins such as antibodies, interferons and complement
Blood plasma
liquid extracellular matrix that contains dissolved substances
Formed elements
cells and cell fragments
Hemopoiesis
formation of blood cells from pluripotent stem cells, occurs in red bone marrow
Red blood cells
biconcave discs without nuclei that contain haemoglobin. lifecycle of 120 days. Haemoglobin is recycled after phagocytosis of aged red blood cells.
Erythropoiesis
RBC formation and occurs in adult red bone marrow. Stimulated by hypoxia, which stimulates release of erythropoietin by kidneys.
Reticulocyte count
diagnostic test that indicates the rate of erythropoiesis.
Pluripotent
can turn into any cell
White blood cells
nucleated cells. classified as either granular leukocytes or agranular leukocytes. function is to combat inflammation and infection.
Granular leukocytes
neutrophils, eosinophils, basophils
Agranular leukocytes
lymphocytes, monocytes
Neutrophils
respond first to bacterial invasion and then macrophages do so through phagocytosis
Eosinophils
combat inflammation in allergic reactions and are effective against parasitic worms
Basophils
involved in inflammatory and allergic reactions and can liberate heparin, histamine and serotonin
Three types of lymphocytes
B cells, T cells and natural killer cells
B cells
develop into plasma cells and produce antibodies that help destroy bacteria and other toxins
T cells
attack viruses, fungi and cancer cells
NK cells
attack a wide variety of infectious microbes and tumor cells
How many WBC does normal blood contain?
5000-10000 per mL.
Platelets
disc shaped fragments without nuclei that are formed from megakaryocytes and take part in hemostasis.
How many platelets does normal blood contain?
150000-400000 per mL
ABO blood group
based on A and B antigens
Rh blood group
named because Rhantigen was first found in bloodof Rhesus monkey. People whose antigens contain Rh antigens are classified as Rh+. Those who lack it are Rh-.
Haemostasis
Sequence of responses that stops bleeding when blood vessels are injured
Three mechanisms that can reduce loss of blood from blood vessels
Vascular spasm, platelet plug formation, blood clotting (coagulation)
Coagulation
Blood clotting
3 stages of blood clotting
formation of prothrombinase, conversion of prothrombin into thrombin, and then thrombin converts soluble fibrinogen into insoluble fibrinogen
How does blood clotting work?
Once a blood clot is formed, it plugs the ruptured area of the blood vessel and stops blood loss. Clot retraction is the consolidation or tightening of the fibrin clot. As blood clot retracts, it pulls the edges of the damaged vessel closer together, decreasing risk of further damage.
What is thrombosis?
Clotting in an unbroken blood vessel.
What is an embolus?
A thrombus that moves from its site of origin
Five types of blood vessels
arteries, arterioles, capillaries, veins and venules
Arteries
carry blood away from heart to body tissues. Their walls consist of three layers - endothelium, smooth muscle and an outer layer. Structure of middle layer gives arteries their two major properties, elasticity and contractility.
Vasoconstriction
decrease in diameter of blood vessel lumen
Vasodilation
increase in diameter of blood vessel lumen
Lumen
inside space of tubular structure
Arterioles
small arteries that deliver blood to capillaries. Through constriction and dilation, arterioles play a key role in regulating blood flow from arteries to capillaries.
Capillaries
microscopic blood vessels that connect arterioles to venules. They are known as exchange vessels because they permit the exchange of nutrients and wastes between body cells and blood.
Precapillary sphincters
regulate blood flow through capillaries
Capillary blood pressure
pushes fluid out of capillaries into interstitial fluid
Blood colloid osmotic pressure
pulls fluid into capillaries from interstitial fluid
Autoregulation
ability of a tissue to automatically adjust its blood flow to match its metabolic demands
Venules
similar in structures to arterioles - their walls are thinner near capillaries and thicker towards heart
Veins
similar structure to arteries but middle and inner veins are thinner. Outer layer is thickest. In some veins, inner layer folds inwards to form valves that prevent backflow of blood. Weak venous valves can lead to varicose veins.
Venous return
refers to movement of blood from capillaries to venules to veins, back to atria of heart. This is aided by skeletal muscle pump and breathing
Cardiac output
volume of blood ejected per minute from left ventricle into aorta. Determined by stroke volume, the amount of blood ejected by left ventricle during each beat
Average stroke volume
70ml
Formula for cardiac output
stroke volume x heart rate
3 factors that regulate stroke volume
degree of stretch in heart before in contracts, forcefulness of contraction of individual ventricular muscle fibers and pressure required to eject blood from ventricles
Where does autonomic regulation of heart rate originate?
in CV centre in medulla oblongata
Other regulators of heart rate
cardiac accelerator nerves, vagus nerves, baroreceptors and chemoreceptors
BP
pressure exerted by blood on walls of a blood vessel. mmHg. depends on total volume of blood
Vascular resistance
opposition of blood flow due to friction between blood and walls of blood vessels. It depends on size of blood vessel lumen, blood viscosity and total blood vessel length
What does the CV centre in the medulla oblongata do?
helps regulate heart rate and stroke volume. Controls neural and hormonal negative feedback systems that regulate BP and blood flow to specific tissues. Also receives input from 3 types of sensory receptors - proprioreceptors, baroreceptors and chemoreceptors
Proprioreceptors
monitor movement of joints and muscles, provide input to CV centre during physical activity to cause rapid increase in heart rate.
Baroreceptors
pressure receptors. Located in aorta, internal carotid arteries and other large arteries in neck and chest. Send impulses to CV centre to regulate BP
Chemoreceptors
monitor blood levels of O2, CO2, and H+. Located in two carotid bodies in carotid arteries and its aortic body. The CV centre responds by increasing sympathetic stimulation of arterioles and veins, producing vasoconstriction and an increase in BP
RAA hormone
Renin-angiotensin-aldosterone kidneys secrete enzyme renin to increase BP
Epinephrine and norepinephrine
sympathetic stimulation increases cardiac output
ADH (hormone)
Andidiuretic hormone - hypothalamus and post pituitary causes vasoconstriction and increased BP
ANP (hormone)
Atrial natriuretic peptide - atria of heart causes vasodilation and lowers BP
Venipuncture
taking blood from veins
Types of bones
long, short, flatg and irregular
Long bones
greater length than width. consist of a shaft and a variable number of ends. not solid as this would be too heavy cavity contains bone marrow curved for strength
Examples of long bones
thigh (femur), leg (tibia and fibula), arm (humerus), forearm (ulna and radius), and fingers and toes (phalanges)
Short bones
cube shaped and nearly equal in length and width.
Examples
most wrist and ankle bones
Flat bones
generally thin, afford considerable protection and provide extensive surfaces for muscle attachment
Examples of flat bones
cranial bone (protect brain), sternum (breast bone), and ribs, which protect organs in the thorax and the scapulae (shoulder blades)
Irregular bones
have complex shapes and cannot be grouped into any other categories. often develop in foetus as two or more bones which then fuse together
Examples of irregular bones
vertebrae and some facial bones.
Partial fracture
an incomplete break across the bone, such as a crack
Complete fracture
a complete break across the bone - broken into 2 or more pieces
Closed (simple) fracture
fractured bone doesn’t break through skin
Open (compound) fracture
broken ends of bone protrude through skin
Epiphysis
growth plate - allows bone to elongate. They close off to prevent further elongation
Repair of fracture
1) phagocytes begin to remove any dead bone tissue
2) chondroblasts form fibrocartilage at the fractures site the bridges the broken ends of the bone
3) fibrocartilage is converted to spongy bone tissue by osteoblasts
4) bone remodeling occurs, in which dead portions of bone are absorbed by osteoclasts and spongy bone is converted to compact bone
Exercise and bone tissue
When placed under stress, bone tissue becomes stronger through increased deposition of mineral salts and production of collagen fibers. Without mechanical stress, bone doesn’t remodel normally because resorption outpaces bone formation. Absence of mechanical stress weakens bone through decreased numbers of collagen fibers and demineralisation, loss of bone minerals
Histology of bone
osteoprogenitor cell develops into osteoblast, osteoblast forms bone extracellular matrix, osteocyte maintains bone tissue
Intramembraneous ossification
Flat bones
1) Mesenchymal cells in embryonic connective tissue develop into osteoblasts.
2) development of ossification centres: osteoblasts secrets organic extracellular matrix
3) calcification: calcium and other mineral salts are deposited and extracellular matrix calcifies
4) formation of trabeculae: extracellular matrix develops into trabeculae that fuse to form spongy bone
5) development of periosteum: mesenchyme at periphery of bone develops into periosteum
Endochondral ossification
1) development of cartilage model: mesenchymal cells develop into chondroblasts which form cartilage model
2) growth of cartilage model: growth occurs by cell division of chondrocytes
3) development of primary ossification center: in this region of diaphysis, bone tissue has replaced most cartilage
4) development of medullary cavity: bone breakdown by osteoclasts forms medullary cavity
5) development of secondary ossification centres: these occur in epiphyses of bone
6) formation of articular cartilage and epiphyseal plate: both structures consist of hyaline cartilage
What is stability related to?
shape of articular surfaces, ligaments and tone of surrounding muscles
Joint
point of contact between bones, between cartilage and bones, or between teeth and bone
Another name for joint
articulation
Arthrology
scientific study of joints
Kinesiology
study of motion of the human body
Criteria for structural classification of joints
1) Presence of absence of synovial cavity
2) Type of connective tissue that holds bones together
Classification of fibrous joints
no synovial cavity and bones are held together by dense irregular connective tissue
Classification of cartilaginous joints
no synovial cavity and held together by cartilage
Classification of synovial joints
synovial cavity and united by dense irregular tissue of an articular capsule, and often by ligaments
Synarthrosis
immovable joint
Amphiarthrosis
slightly movable joint
Diarthrosis
freely movable joint
Fibrous joints
permit little or no movement
Three types:
1) syndesmoses - permits limited movement (distal tibia and fibula) and gomphosis (dentoalveolar joint)
2) suture - slightly movable or immovable (found between skull bones)
3) interosseous membrane - permit slight movement (between radius and ulna and tibia and fibula)
Cartilaginous joints
allows little or no movement
Two types:
1) synchondrosis - immovable joint (epiphyseal plate)
2) symphysis - slightly movable joint (pubic symphysisand intervertebral joints)
Synovial joints
allows free movement of joint
synovial membrane secretes synovial fluid, which forms a thin, viscous film over the surfaces within the articicular capsule
Bursae
sac like structures, similar in structure to joint capsules, that reduce friction in joints such as the shoulder and knee joints
Synovial cavity
space between articulating bones
Gliding
movement at synovial joints
nearly flat surfaces of bones move back and forth and side to side
Angular movement
at joints
increase or decrease in angles between bones
Rotation movement
at joints
bone moves around its own longitudinal axis
Special movements
only at certain points in body
6 types of synovial joints
plane, hinge, pivot, condyloid, saddle, and ball and socket
Plane synovial joint
articulating surfaces are flat
bones glide
may also permit rotation
e.g. between carpals and between tarsals
Hinge synovial joint
convex surface of one bone fits into concave surface of another
motion is angular around one axis
e.g. elbow, knee and ankle joints
Pivot synovial joint
round or pointed surface of one bone fits into a ring formed by another bone and a ligament
movement is rotational (uniaxial)
e.g. atlantoaxial and radioulnar joints
Condyloid synovial joint
oval projection of one bone fitsinto oval cavity of another
motion is angular biaxial
e.g. wrist joint
Saddle synovial joint
articular surface of one bone is shaped like a saddle and the other bone fits into the saddle
motion is angular biaxial
Ball and socket synovial joint
ball shaped surface of one bone fits into cuplike depression of another
motion is triaxial
e.g. shoulder and hip joints
Knee joint
largest, most complex joint in body
contains articular capsule, several ligaments within and around outside of joint, menisci and bursae
Arthroplasty
surgical replacement of damaged natural joints with superficial ones
Myology
scientific study of muscles
Three types of muscular tissue
skeletal, smooth and cardiac
Skeletal muscle basic info
mostly attached to bones, striated and voluntary
Cardiac muscle basic info
forms most of heart wall - striated and involuntary
Smooth muscle basic info
located in viscera - non striated and involuntary
Striated
ability of light to get through - creates lines
Tendons
extensions of connective tissue beyond muscle fibers that attach the muscle to the bone
Histology of skeletal muscle tissue
muscle fibers covered by plasma membrane called sarcolemma.
transverse tubules tunnel in from surface towards centre of each muscle fiber.
What do skeletal muscle fibers contain?
sarcoplasm, multiple nuclei, many mitochondria, myoglobin, and sarcoplasm reticulum
also contain myofibrils that contain thick and thin filaments
How are thick and thin filaments arranged?
arranged in functional units called sarcomeres.
What do thick filaments consist of?
myosin
What are thin filaments composed of?
actin, tropomyosin and troponin
How are sarcomeres separated from each other?
by zigzagging zones of dense protein material called Z discs
Within sarcomeres
a darker area called the A band extends the entire length of thick filaments. At centre of A band is a narrow H zone which contains only the thick filaments. At both ends, thin and thick filaments overlap. A lighter coloured area on either side of A band is the I band which only contains the rest of the thin filaments
Sliding
filament mechanism - sliding of filaments and shortening of sarcomeres that cause the shortening of muscle fibers
Contraction cycle
1) splitting ATP - myosin ATPase splits ATP and becomes energised
2) forming cross bridges - myosin head attaches to actin, forming a cross bridge
3) Power stroke - cross bridg generates force as it swivels or rotates towards centre of sarcomere
4) binding ATP and detachment - myosin detaches from actin. Cycle repeats
Summary of contraction and relaxation
1) nerve impulse arrives at axon terminal of motor neuron, triggers release of ACh
2) ACh diffuses across synaptic cleft, binds to its receptors in motor end plate and triggers muscle action potential
3) Acetyl Cholesterase in synaptic cleft destroys ACh so another action potential does not arise unless more ACh release
4) Muscle AP opens Ca2+ release channels in SR membrane, which allows calcium ions into sarcoplasm
5) Ca2+ binds to troponin, exposing binding sites for myosin
6) Contraction cycle
7) Ca2+ release channels close and Ca2+ active transport pumps use ATP to restore low level of Ca2+ in sarcoplasm
8) Troponin-tropomyosin complex slides back into position where it blocks the myosin binding sites on actin
9) Muscle relaxes
Exercise and skeletal muscle tissue
Relative ratio of FG and SO fibers in each muscle is genetically determined and helps account for individual differences in physical performances.
What are people with a higher proportion of FG fibers good at?
intense activities e.g. strength training
What are people with a higher proportion of SO fibers good at?
activities which require endurance
What produces an increase in size and strength of FG fibers?
Exercises that require great strength for short periods due to increased synthesis of thick and thin filaments
Cardiac muscle tissue
each cardiac muscle fiber contains a single centrally located nucleus and exhibits branching.
muscle fibers connected by intercalated discs which hold muscle fibers together and allow muscle action potentials to quickly spread from one MF to another
How does Cardiac muscle tissue contract?
contracts when stimulated by its own autorhythmic fibers. Due to its autorhythmicity, cardiac muscle depends greatly on aerobic cellular respirate to generate ATP
What does smooth muscle tissue contain?
contain thick and thin filaments, intermediate filaments and dense bodies
Visceral smooth muscle tissue
found in walls of hollow viscera and of small blood vessels. Many visceral fibers form a network that contracts in unison
Multiunit smooth muscle tissue
found in large blood vessels, large airways to the lungs, arrector pili muscles and the eye. The fibers contract independently
Smooth muscle tone
state of continuous partial contraction of smooth muscle tissue
Stretching of smooth muscle fibers
can be stretched considerably and still retain the ability to contract. they contract in response to nerve impulses, stretching, hormones and local factors
How do skeletal muscles produce movement?
skeletal muscles pull on tendons, which pull on the bones.
attachment to stationary bone is the origin
attachment to movable bone is insertion
agonist produces desired movement - antagonist produces opposite movement. synergist assists prime mover by reducing unnecessary movement. fixator stabilises origin of prime mover so it can act more efficiently
What attaches muscle to bone?
Tendons
Calcium homeostasis is controlled by…
parathyroid hormone
Coxal joint
ball and socket joint between bones of pelvis and femur
Disease associated with lack of Vitamin D?
Rickets
Deltoid
muscle in upper arm
Larnellar granules
release lipids which inhibit evaporation of water from skin surface
Components of epidermis
composed of keratinized, stratified squamous epithelium which contains 4 types of cells:
keratinocytes - 90% of epidermal cells, produce keratin
melanocytes - 8% of cells, produce melanin
Intraepidermal macrophages - participate in immune responses
Tactile epithelial cells - detect touch sensations
Keratinization
newly formed cells in stratum basale are slowly pushed to surface. As cells move from one layer to the next, they accumulate more and more keratin. Eventually the keratinized cells slough off and are replaced by underlying cells
4 layers of epidermis
stratum basale - deepest layer
stratum spinosum - provides strength and flexibility
stratum granulosum - keratinocytes undergo apoptosis here
stratum corneum - most superficial layer
5th layer of epidermis
only in palms and soles
stratum licidium - below corneum when present
Dermis components
superficial part consists of areolar connective tissue containing fine elastic fibers. Its surface area is greatly increased by small fingerlike projections called dermal papillae, touch receptors and free nerve endings
Hair
thread of fused, dead, keratinized epidermal cells that consist of a shaft, a root and a follicle.
Associated with hairs
bundles of smooth muscle called arrector pili and sebaceous glands, which are usually connected to hair follicles.
Sebaceous glands produce..
sebum which moistens hair and waterproofs the skin
Grey hair
due to a decline in melanin
White hair
due to an accumulation of air bubbles in hair shaft
Sudoriferous glands
sweat glands (apocrine and eccrine)
Nail components
nail body, free edge, nail root, lunula, cuticle and nail matrix
role of secretin
a hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver.
Respiratory acidosis
a medical emergency in which decreased ventilation increases the concentration of carbon dioxide in the blood and decreases the blood’s pH
Respiratory alkalosis
a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a reduction in arterial levels of carbon dioxide.
Hypoventilation
decreased ventilation
Hyperventilation
increased ventilation
Tachycardia
an abnormally rapid heart rate.
Bradycardia
abnormally slow heart action.
Sinus rhythm
a normal heart beat, both with respect to the heart rate and rhythm.
Thrombus
a clot of blood formed within a blood vessel and remaining attached to its place of origin.
Peripheral resistance
the resistance of the arteries to blood flow. As the arteries constrict, the resistance increases and as they dilate, resistance decreases.
Effect of ageing of skeletal system
From about age 30, the density of bones begins to diminish in men and women. This loss of bone density accelerates in women after menopause. As a result, bones become more fragile and are more likely to break (see Osteoporosis), especially in old age.
Reasons for muscle fatigue
impaired blood flow, ion imbalance within the muscle, nervous fatigue, loss of desire to continue, and most importantly, the accumulation of lactic acid in the muscle.
Effect of sunlight on skin
exposure to sunlight causes the skin to produce more melanin and to darken. The tan fades as these cells move toward the surface and are sloughed off.
Epidermal growth factor (EGF)
stimulates cell growth, proliferation, and survival.
How does the endocrine system transport hormones around the body?
Releases hormones into interstitial fluid and then into bloodstream
How do exocrine glands transport secretions?
Secrete products into ducts that carry them into body cavities, lumen or organs or the outer surface of the body.
Functions of hormones
Regulation, control growth and development, regulate operation of reproductive system and help establish circadian rhythms
Proper name for anterior pituitary
Adenohypophysis
Proper name for posterior pituitary
Neurohypophysis
Name for middle section of pituitary
Pars intermedia
Hormone action
affects only specific target cells that have specific protein receptors to bind to a given hormone
Which hormones are lipid soluble?
steroids, thyroid, nitric oxide
Which hormones are water soluble?
modified amino acids, peptides and proteins
How do lipid soluble hormones alter cell function?
- Hormone diffuses into cell
- Hormone attaches to receptor to form receptor-hormone complex which alters gene expression
- Newly formed mRNA directs synthesis of specific proteins or ribosomes
- New protein alters cell activity
How do water soluble hormones alter cell function?
- Hormone binds to receptor
- ATP converted to cAMP
- cAMP serves as second messenger to activate certain proteins
- activated proteins cause reactions that produce physiological responses
- cAMP is inactivated
Stress response flow chart
Stimulus - Hypothalamus in limbic region - Sympathetic tracts - Adrenal Medulla - Adrenalin - Bloodstream - All tissues (Adenoceptors) - Activity (Increased heart and respiratory rate, diaphoresis)
Term for sweating
Diaphoresis
Term for adrenaline
Epinephrine
Exhaustion after stress response
results from depletion of body resources during resistance phase.
Effect of prolonged exposure to cortisol in resistance reaction
causes wasting of muscles and suppression of immune system
Hormones produced by anterior pituitary
hGH, PRL, ACTH, TSH, FSH, LH, MSH
Hormones produced by posterior pituitary
Oxytocin and ADH
hGH
Human Growth Hormone - stimulates body growth
PRL
Prolactin - initiates and maintains milk production by mammary glands
ACTH
Adrenicorticotropic hormone - regulates activities of adrenal cortex
TSH
Thyroid stimulating hormone - regulates thyroid gland activities
FSH and LH
Follicle stimulating hormone and Luteinizing hormone - regulates activities of gonads
MSH
Melanocyte stimulating hormone - causes darkening of skin
Oxytocin
stimulates contraction of uterus and ejection of milk from breasts - stimulated by uterine stretching and suckling during nursing
ADH
Antidiuretic hormone - stimulates water reabsorption by kidneys and constriction of arterioles - controlled by osmotic pressure of blood and blood volume
Thyroid structure
butterfly shaped, located just below larynx. Composed of right and left lobes, one on each side of trachea.
What do thyroid lobes release?
thyroid hormones T3 and T4, and parafollicular cells
T3
triiodothyronine
T4
thyroxine or tetraiodothyronine
What do parafollicular cells do?
secrete calcitonin which can lower levels of calcium in blood
What do thyroid hormones do?
regulate oxygen use, metabolic rate and cellular metabolism
Flow diagram for regulation of secretion of thyroid hormones
Hypothalamus secrets releasing factor - Anterior pituitary releases TSH - Thyroid releases T3 and T4
Parathyroid glands
located of posterior surface of thyroid.
Parathyroid hormone
regulates homeostasis of electrolytes
Flow diagram for blood levels of calcium
Stimulus increases blood Ca2+ levels - Thyroid stimulates parafollicular cells - release more calcitonin to inhibit osteoclasts - decreased blood Ca2+ levels
cAMP
Cyclic Adenosine Monophosphate
Second messenger which helps to transfer hormones into the plasma membrane by intracellular signal transduction
Adrenaline
produced in medulla of adrenal glands. Prepares body for fight or flight response. Controlled by activation of nerves connected to adrenal glands. When stress is over, nerve impulses are lowered to stop production of adrenaline
Normal level of calcium
8.6-10.2 mg/dL
Normal levels of Potassium
3.5-5.0 mEq/L
Normal level of ammonia
15-50 umol/L
Normal level of Chloride
95-105 mmol/L
Normal level of glucose
65-110 mg/dL
Normal level of Sodium
135-145 mmol/L
Negative feedback system of ACTH
Hypothalamus releases CRH - Anterior PItuitary releases ACTH - Adrenal Cortex releases cortisol - affects blood levels of cortisol
5 functions of skin
Body temp. regulation Protection Cutaneous sensations Excretion + absorption Synthesis of Vitamin D
3 layers of skin
Epidermis, dermis, subcutaneous
Epidermis composition
Superficial, thinner portion, composed of keritinized, stratified, squamous epithelial tissue
Dermis composition
made of dense, irregular, connective tissue
4 types of cells in epidermis
Keratinocytes
Melanocytes
Intraepidermal macrophages - help in immune responses
Tactile epithelial cells - detect touch
Keratinization
newly formed cells in stratum basale are slowly pushed to surface. As cells move up epidermal layers, they accumulate more and more keratin. Eventually the keratinized cells slough off and are replaced by underlying cells
4 layers of epidermis (bottom to top)
stratum basale
stratum spinosum
stratum granulosum
stratum corneum
Role of stratum granulosum
where keratinocytes undergo apoptosis
Role of stratum spinosum
provide strength
Layer of epidermis in palms and soles
stratum lucidum - below corneum when present
How is surface area of dermis increased?
by small fingerlike projections called dermal papillae, touch receptors and nerve endings
Accessory structures of integumentary system
Hair, sweat glands, nails
Hair
thread of fused, dead, keratinized epidermal cells that consist of a shaft, root and follicle
Associated with hairs
bundles of smooth muscles called arrector pili and sebaceous glands.
What do sebaceous glands produce?
cebum which moistens hair and waterproofs the skin
Reason for grey hair
decline in melanin
Reason for white hair
accumulation of air bubbles in the hair shaft
Nail components
nail body, free edge, nail root, lumula, cuticle and nail matrix
Nociceptors
pain receptors. Naked nerve endings so top can be sliced off.
Two stages macrophages take part in
Chemotaxis and Phagocytosis
Chemotaxis
recognising chemicals
3 pigments in skin colour
melanin, carotene and hemoglobin
Insensitive manor
cannot calculate (e.g loss of water through sweat)
Role of Vitamin D
regulates calcium and phosphate in body, which keep teeth and bones healthy
Manufacture of Vitamin D
Produced in skin when exposed to sunlight, which breaks the B ring to form pre D3 which then isomerises to form D3. The liver and other tissues metabolise this to 250HD, which is then synthesised to 1,25(OH)2D in the kidney.
250HD
principal circulating hormonal form of Vitamin D
1,25(OH)2D
main form of Vitamin D which performs functions
