learning outcomes Flashcards
Explain the differences between EC and IC fluid compartments ?
Extracellular fluid :
- Fluid outside the cell found in blood plasma
- Major ECF cation is Na+ with balancing anions Cl- and HCO3-
Intracellular fluid :
-Fluid inside the cell found in the cytoplasm
- A low pH
- Major ICF cations K+ and Mg2+.
Both use osmosis
List examples of different organ systems ?
1) Musculoskeletal system: a framework for movement and posture (striated muscles and tendons).
2) Immune system : a biological processes protecting organism against disease by identifying and killing pathogens , found in lymph nodes.
3) Integumentary system : prevents water loss and regulates body temperature.
4) Lymphatic system : is key for immunity and blood pressure regulation
The concept of homeostasis ?
Homeostasis helps the body maintain vital parameters around a set point using negative/positive feedback mechanisms :
water temperature
waste regulation
What is an example of homeostasis ?
Core temperature
Plasma level of oxygen
Inorganic ion concentration Na+, Ca+, H+)
Energy levels ATP)
What is an hormone ?
lipid based chemical messengers secreted into the blood
Give examples of 2 hormonal feedback ?
Negative feedback : underpins homeostatic regulation of nearly all organ systems
Physiologic response ‘feeds back’ directly or indirectly to the endocrine gland to regulate its secretion
Positive feedback : causes greater secretion of a hormone
Describe the structure of the heart ?
3 walls of the heart:
1) Epicardium
2) Myocardium
3) Endocardium
large blood supply
temperature regulation
unidirectional flow
List the 3 types of blood vessels ?
1 ) Capillaries : Exchange of materials in capillary beds
2) Veins : collect oxygen-poor blood
3) Arteries : bring oxygen-rich blood
Describe the differences between blood vessels ?
1 ) Capillaries : only endothelial layer on basement membrane
Large surface area and thin diffusion barrier.
2) Veins : have low resistance and one way valves, act as reservoirs for blood.
3) Arteries : have thick elastic and smooth muscle walls to maintain blood pressure around the body
Explain the differences between systemic and pulmonary pressure.
Systemic pressure : the mean pressure that exists in the circulatory system when there is no blood motion.
Pulmonary pressure : when the pressure in the blood vessels leading from the heart to the lungs is too high.
Systemic circulation transports oxygenated blood from the heart throughout the body.
pulmonary circulation brings deoxygenated blood back to the heart.
What is the relationship between the cardiovascular and respiratory system ?
Respiratory and cardiovascular systems work together to maintain oxygen levels to meet the body’s needs for cellular respiration.
3 types of chemoreceptor:
central receptors in the medulla oblongata;
carotid bodies in the walls of the carotid arteries
aortic bodies on the (peripheral receptors)
Describe the structure of the lung ?
Surrounded by pleural membranes attaching lungs to ribcage and diaphragm
Contraction of large muscular diaphragm induces inhalation
Gaseous exchange between air and blood occurs at the alveoli
How does gas exchange occur ?
1) Diffusion of O2 from alveolus to blood capillary to combine with hemoglobin.
2) Ventilation and blood flow maintain concentration gradients to maximize diffusion
List lung volume and how its determined ?
Lung volumes :
Vital capacity
Residual volume
Total lung capacity
Its determined by a spirometer and peak flow meter
Describe the structure of the digestive system ?
mouth, esophagus, stomach, small intestine, large intestine, and anus.
Explain the function of each segment along the alimentary canal ?
it’s a long coiled muscular tube from mouth to anus that hydrolysis and absorbs food molecules
Four basic layers throughout:
Mucosa: muscle
Submucosa– Dense connective tissue
Muscularis externa– two smooth muscle layers
Serosa(Outermost layer) – collagen
What is the role of accessory organs ?
Liver: produces
Water
Bile salts
Mucus
Cholesterol
What is the process involved in digestion ?
1) Ingestion: mouth
2) Digestion: Stomach
3) Absorption: small intestine
4) Assimilation : delivering the absorbed food in blood
5) Egestion : Anus
What is the anatomy of the kidneys (macro / micro structure ) ?
- The kidney is responsible for removal of nitrogenous waste through blood filtration.
- Highly vascular bean-shaped organs, functional units = nephrons
- Kidney has outer cortex and inner medulla
- Renal artery splits into many capillaries
What is the structure of a nephron ?
Glomerulus
Bowman’s capsule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting duct
What is the function of each part of the nephron?
Glomerulus: large surface area of blood capillaries
Bowman’s capsule : Filtration from blood under hydrostatic pressure
Proximal convoluted tubule : Most filtrate formed in the renal capsule reabsorbed from the PCT into capillaries . Amino acids, glucose and sodium are removed by secondary active transport. All reabsorption starts with Na+K+ATPase lowering intracellular Na+ concentration
Loop of Henle : As fluid travels up the ascending limb, Na+ Cl- is actively transported into the surrounding area , which causes water to pass out of the descending limb by osmosis .
Distal convoluted tubule : role in regulation of pH, salt and water balance. Na+ ions are actively pumped out, Cl- follows passively
Collecting duct : Urine enters the CD – travels through themedullato thepelvis.Aquaporinsin the membrane which allow additional water to escape through.
What is the structure of a neurone ?
Dendrites
Cell body
Axon
Nerve terminal
Neurons are responsible for sending and receiving neurotransmitters
The difference between CNS and PNS ?
Central nervous system : is the brain and spinal cord
Peripheral nervous system : consists of the nerves that branch out from the brain and spinal cord.
What is the function of the somatic nervous system ?
Controls voluntary movements by skeletal muscles : joints and eyes
What is the function of the automic nervous system ?
regulates involuntary processes
including heart rate, blood pressure, respiration, digestion.
What are the phases of a neuronal action potential and the ion channels involved ?
Neurones have selectively permeable membranes with ion channels and protein pumps
Na+K+ transporter actively transports 3 Na+ ions out of cells and 2 K+ ions in
In addition K+ and Na+ channels
Therefore positive ions accumulate outside cells providing a resting potential
What is saltatory conduction?
the way an electrical impulse skips from node to node to another down the axon, which speed the arrival of the impulse at the nerve terminal.
Advantages :
The conduction of nerve impulses is fast
More energy efficient
What is the function of myelin ?
Myelin is a sheath that forms around nerves and allows electrical impulses to transmit quickly and efficiently along the nerve cells.
Examples of a neurotransmitter ?
Acetylcholine
What is passive transport ?
1) Protein channels provide hydrophilic passage for water and small, polar ions.
2) Size and shape allow the transmission of specific molecules.
3) Protein carriers are highly selective. Binding a solute on one side of the membrane and delivering it to the other side through conformational change.
4) Transport may be passive or actively coupled to the electrochemical gradient of another solute.
What is active transport ?
1) Molecules moving against their concentration gradient using ATP hydrolysis
2) Na+- K+ pump present in membranes of all cells
3) Pumps 3 Na+ from ICF to ECF and 2 K+ in reverse, establishing a potential difference.
The role of Oesophagus ?
- Swallowed food passes from pharynx to stomach via muscular tube .
- Elastic tissue allows expansion.
- Stratified epithelium protects against friction damage.
The role of the stomach ?
Contains in the stomach :
HCl
Enzymes
Mucous
- Provides optimum pH for pepsin and renin
- Denatures proteins and aids the breakdown of connective tissue
The role of small intestine ?
main site digestion and absorption
- Brush border lined with microvilli higher surface area , embedded enzymes.
- Contains pancreatic juice which neutralise stomach acid
The role of the large intestine?
Colon – water and ion absorption (Cl-, K+, Vitamins)
Rectum – forms and stores faeces
Anus – ejects faeces
The role of villa in the small intestine ?
Only one cell thick
Rapid absorption
What is amino acid transport ?
1) Amino acids and small peptides also use ATP to absorb into the blood.
2) Amino acid-Na+ symporter on apical membrane
3) Na+K+ATPase on basolateral membrane to establish Na+ gradient
What are the 3 sections of the small intestine :
Duodenum
Jejunum
Ileum
What is hydrophilic molecule ?
Hydrophilic peptide hormones travel in blood but only affect cells with specific receptor proteins on their surface. Which brings changes inside the cell
What is hydrophobic molecule ?
Hydrophobic steroid hormones pass easily into cells through the lipid bilayer
Bind to intracellular target receptor molecules within the cytoplasm
Switching on or off gene expression
What are the 3 areas of the brain ?
Forebrain : Responsible for hunger and thirst and helps control the ANS as it regulates body temperature and water/salt balance (hypothalamus)
Midbrain : associated with vision, hearing, motor control and temperature regulation.
Hindbrain :
Medulla oblongata : end of brainstem controlling heart rate, breathing, and blood supply
Pons : transfers messages between various parts of the brain and the spinal cord
Cerebellum: controls body movement and maintains balance
What are the 3 types of neurones ?
Sensory neurone (afferent) : activated by sensory input from the environment.
Relay neurone : messages between other neurones, sensory + motor.
Found most often in brain + spinal cord
Motor neurone (efferent ) : Carry impulses from CNS to effectors to initiate a response
How neurone synapse transmission occur?
Membrane ion channels (membrane permeability K+ > Na+)
Nerve impulse - electrical signal (action potential)
Change in ion balance travels from one end of the cell to the other
Connects to another neurone at junction (synapse) via a chemical transmitter
Myelinated vs non-myelinated neurones ?
Unmyelinated neurones - each section of membrane depolarises the next, so transmission of nerve impulse is relatively slow
Myelinated neurone - impulse jumps from one node to the next, so only membrane of the nodes depolarised leading to rapid transmission (saltatory conduction)
What occurs in the presynaptic bulb ?
1) Action potential reaches the presynaptic terminal depolarizing membrane.
2) Opens voltage-gated Ca2+ channels
3) Vesicles containing neurotransmitters fuse with the presynaptic membrane.
4) Neurotransmitter is released into the synaptic cleft.
What is the 3 synapse components ?
The presynaptic ending contains neurotransmitters.
The synaptic cleft between the two nerve cells.
The postsynaptic ending contains receptor sites.
