Midterm Review Flashcards
What is a function?
It explains why something happens
What is a mechanism/process?
It describes how something happens
What is the overview of the body? (In what order is the body structured)
- Chemical level
- Cells
- Tissues
- Organs
- Systems
- Human organism
What must the body be able to do to maintain homeostasis?
- Detect deviations from normal in the internal environment
- Integrate this information with other relevant information
- Make appropriate adjustments
What is set point?
Normal range for a given system
What are intrinsic controls?
Local controls that are inherent in an organ (within an organ)
What are extrinsic controls?
Regulatory mechanisms initiated outside an organ, accompanied by nervous and endocrine systems
What is the difference between feedback and feedforward loops?
Feedback respond to a change (positive and negative), feedforward anticipates a change
What are the basic components of a feedback loop?
Stimulus, controlled condition, receptors, control centre, effectors, response
What are the components of a feedback loop?
Sensor, control system and effectors
What is an example of a negative feedback loop?
Blood pressure regulation
What is an example of a positive feedback loop?
Contractions during labour, blood clotting
What is a disorder?
General term of derangement of abnormality of function
What is a disease?
More specific term for an illness characterized by a recognizable set of signs and symptoms
What is an example of a feedforward mechanism?
Saliva production prior to eating preps digestion of carbs, food in stomach increases insulin production to promote uptake and storage of nutrients
How are feedforward mechanisms regulated?
Through central command, i.e. when about to exercise our body primes our system for the change during exertion
What are the four types of macromolecules?
Carbs
Proteins
Fat
Nucleic acids
What are the main types of carbs?
Monosaccharides (1 sugar), disaccharides (2 sugar), polysaccharides (many sugars)
What are the monosaccharides?
Glucose, fructose and galactose
What is glucose used for?
ATP
What is fructose used for?
Aid in glycolysis and helps replenish liver glycogen stores
What are the disaccharides?
Sucrose (glucose + fructose), Maltose (glucose + glucose), lactose (glucose + galactose)
What are the polysaccharides?
Starch (amylose and amylopectin), glycogen, cellulose (most naturally abundant polysaccharide), chitin
What are proteins used for?
- Catalyzing chemical reactions
- Synthesizing and repairing DNA
- Transporting materials across cell
- Receiving and sending chemical signals
- Responding to stimuli
- Providing structural support
How many amino acids are required by the body?
20
What are enzymes?
They catalyze chemical reactions
What is an anabolic enzyme?
An enzyme that builds something more complex
What is a catabolic enzyme?
An enzyme that breaks down their substrate
What are examples of some catabolic enzymes used for digestion?
Amylase (carbs), pepsin (proteins in stomach), lipase (fats in S.I) and trypsin (proteins in S.I)
What is an example of a protein hormone?
Insulin
What are the three types of fats?
Fats
Phospholipids
Steroids
What are fats made of?
One glycerol and three fatty acids
What is the difference between saturated fats and unsaturated fats?
Saturated - no double bonds present, maximum amount of H atoms, forms solids
Unsaturated - One or more double bonds present, forms liquid
What are phospholipids and what are they used for?
They’re made up of two fatty acids and a phosphate group and they’re used for the outer layer of cell membranes
What do steroids do?
Play roles in reproduction, absorption, metabolism regulation and brain activity
What is the structure of a steroid?
4 linked carbon rings (fused structure)
What is the most common steroid?
Cholesterol (precursor to vitamin D and many other hormones in the body)
What does energy intake equal?
internal heat produced + external work + internal work + energy storage
What are the three possible states for energy balance?
Neutral, positive (input greater than output, therefore weight gain), and negative (input less than output, therefore weight loss)
How is metabolic rate defined?
Energy expenditure/Unit of time
What is basal metabolic rate (BMR)?
The minimal internal energy expenditure we need to maintain in order for our body’s to function
What are some factors that influence metabolic rate?
Thyroid hormone levels
Sympathetic stimulation (epinephrine or norepinephrine)
Exercise
Daily activities
Sex/gender
Age
What is a competitive inhibitor?
An inhibitor that is similar enough to the substrate it can bind at the active site, competes with substrate
What is non-competitive inhibitor?
The inhibitor binds to a location other than the active site (allosteric site), then it changes the shape of the enzyme
What is an allosteric activator?
Attaches to an allosteric site to increase the enzyme’s affinity for a substance, speeds up reaction rate
What is a cofactor or a coenzyme?
Promotes optimal conformation and function for their respective enzymes
What is feedback inhibition?
A process through which the product regukates its own production
What are the most common fuels for monosaccharides, lipids and proteins?
Glucose, triglycerides (ina process called B-oxidation), and amino acids
What type of reactions are very important in energy transfer?
Oxidation-reduction reactions
What are the three main phases for cellular respiration?
Glycolysis
Kreb’s Cycle
Electron transport chain
What happens during the process of glycolysis?
The breakdown of glucose into pyruvate
What is glycogenolysis?
The breakdown of glycogen into glucose
Where does glycolysis occur?
In the cytosol of the cell
What is used and what is produced during glycolysis?
Takes 2 ATP and 2 NAD+ to convert 1 glucose into 2 pyruvate, 4 ATP and 2 NADH
What is the rate limiting (on or off switch/allosteric regulation) enzyme in glycolysis?
Phosphofructokinase (PFK)
How do we up regulate glycolysis?
High levels of AMP means that the cell is low on energy and that glycolysis must occur to replenish these stores
How do we down regulate glycolysis?
ATP is a negative regulator of PFK, and citrate building up
Where does the kreb’s cycle take place?
In the matrix of mitochondria
What goes in and comes out of the Krebs cycle?
2 pyruvate and 2 Acetyl CoA make 2 ATP, 8 NADH, 2 FADH2 and CO2 in two cycles
Where does the bulk of ATP come from in cellular respiration?
Electron transport chain
What is the process of chemiosmosis?
It involves the pumping of protons through special channels from the inside of the mitochondria to the outside of the mitochondria (establishes a gradient)
How many ATP do we get from the electron transport chain?
34 ATP (38 ATP from the whole process)
How many ATP can we get out of one NADH and one FADH2?
1 NADH = 3 ATP
1 FADH2 = 2 ATP
What is the real number of ATp generated from cellular respiration?
30-32 ATP
What is fermentation?
When there is not enough oxygen for the body to carry out the full process of cellular respiration the pyruvate from glycolysis get converted to lactic acid and stored to allow glycolysis to continue
What happens to the accumulating lactate?
When it builds up in the muscles it it then transported to the liver via the circulatory system and is then processed there (also used for a fuel source in the brain)
What happens to the to the NADH that is produced during fermentation?
It is used to make the pyruvate and the NAD+ produced from the process of making the pyruvate can therefore be recycled and used for glycolysis again
How do we obtain energy from fat?
Fat is broken down by hydrolysis, then through a process called lipolysis that takes place in the cytoplasm, b-oxidation turns it into acetyl-CoA
How do we use protein as fuel?
They are broken down into amino acids and act as pyruvate/acetyl CoA in the krebs cycle
What is an endocrine hormone?
One that travels in the blood and acts on distant target cells
What is a paracrine hormone?
One that acts on neighbouring cells
What is an autocrine hormone?
One that acts on the same cell that secreted the hormone
What is a lipid-soluble (steroid, thyroid) hormone?
Circulate bound to proteins and diffuse across plasma membranes, bind to receptors within target cells
What are water soluble (amine, peptide and protein) hormones?
Circulate freely in plasma, bind to receptors on the exterior of the cell, activates a second messenger response, can be excitatory or inhibitory
What does up-regulation mean in terms of hormones?
Receptors will become more sensitive in the presence of low concentrations of hormone
What does down-regulation mean in terms of hormones?
Receptors become less sensitive in the presence of high concentrations of hormones
What is the response of a target cell based on?
The hormones concentration in the blood, the number of hormone receptors on the target cell, can be influenced by other hormones (synergistic effect or antagonistic effect)
What is the secretion of hormones regulated by?
Chemical changes in the blood, signals from the nervous system and other hormones
What type of control are most endocrine glands under?
Negative feedback control
What is the main link between the nervous system and the endocrine system?
The diencephalon (the hypothalamus)
What are the 7 hormones released by the hypothalamus?
Thyrotropin releasing hormone (TRH)
Corticotropin releasing hormone (CRH)
Gonadotropin releasing hormone (GnRH)
Prolactin releasing hormone (PRH)
Growth hormone releasing hormone (GHRH)
Growth hormone inhibiting hormone (GHIH) (somatostatin)
Prolactin inhibiting hormone (PIH) (dopamine)
The pituitary is connected to the hypothalamus by what?
The infundibulum
How do the hormones travel from the hypothalamus to the pituitary gland?
Through the hypophyseal portal system
What hormones are secreted from the anterior pituitary?
Human growth hormone (hGH) is secreted by somatotrophs
Prolactin (PRL) is secreted by lactotrophs
Thyroid stimulating hormone (TSH) is secreted by thyrotrophs
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are secreted by gonadotrophs
Adrenocorticotropic hormone (ACTH) and melanocyte-stimulating hormone (MSH) are secreted by corticotrophs
What to hormones control hGH?
GHIH and GHRH
What does FSH do in males and females?
Males: stimulates sperm production
Females: initiates follicle development and secretion of estrogens
What does LH do in males and females?
Males: stimulates the interstitial cells to secrete testosterone
Females: stimulates the secretion of estrogen to result in ovulation and stimulates the formation of the corpus luteum and the release of progesterone
What does ACTH do?
Controls the production and secretion of hormones called glucocorticoids by the adrenal cortex
What does the posterior pituitary store and release?
Oxytocin (OT) and Anti-diuretic hormone (ADH)
How is ADH used in the body?
Osmoreceptors monitor osmotic blood pressure and release ADH when blood volume is too low, if the blood volume increases the body will stop secreting ADH
What type pf cells are in the thyroid gland?
Follicular cells and parafollicular cells
What do the follicular cells secrete?
Thyroid hormones (thyroxine T4, and triiodothyronine T3)
What do the thyroid hormones do?
Increase metabolic rate
Help maintain normal body temp
Stimulate protein synthesis
What do the thyroid hormones actively do to the body when released?
Increase the use of glucose and fatty acids for ATP production
Upregulate beta (B) receptors that attach to catecholamines
Work with hGH and insulin to accelerate body growth
What do the parafollicular cells secrete?
Calcitonin (lowers the levels of calcium in the blood)
What does the parathyroid secrete?
Parathyroid hormone (PTH)
What does parathyroid hormone do?
Increases the rate of calcium absorption by kidneys
Promotes formation of calcitriol which helps with reabsorption from the GI tract
Increased osteoclast activity
What hormones are secreted by the adrenal cortex?
Mineralocorticoids (aldosterone) - regulate mineral homeostasis
Glucocorticoids (cortisol) - affect glucose homeostasis
Androgens (DHEA) - masculinizing effects
What does aldosterone regulate?
Major in potassium and sodium balance in the body
What pathway controls the secretion of aldosterone?
The renin-angiotensin-aldosterone (RAA) pathway
What does cortisol help regulate?
Protein breakdown
Glucose formation
Lipolysis
Resistance to stress
Inflammation
Immune responses
What is dehydroepiandrosterone (DHEA) used for?
In females DHEA is used to promote libido and are converted to estrogens
In males it doesn’t play a big role after puberty
What does the adrenal medulla secrete?
Catecholamines (epinephrine and norepinephrine)
What do the Alpha cells in the pancreas secrete?
Glucagon (increase blood sugar)
What do the Beta cells in the pancreas secrete?
Insulin (decrease blood sugar)
What does the thymus do?
Promotes the maturation of T cells
What are examples of anabolic hormones?
Growth hormone, insulin, testosterone and estrogen
What does the pineal gland secrete?
Melatonin
What are examples of catabolic hormones?
Cortisol, glucagon, adrenaline/epinephrine and cytokines
What happens with glucose regulation in a fed state (glucose is high)?
Insulin is released and glucose uptake is increased and stored (get glucose into cells)
What happens with glucose in a fasting state (glucose is low)?
Glucose is released from tissues (liver) and cells into the blood, breakdown of glycogen, formation of ketones
How do cells respond to insulin?
They have insulin receptors on their membranes and respond by mobilizing and inserting glucose-transporter proteins into their membranes, which increases glucose entry
How is glucose regulated in the liver?
Through GLUT2
What is the enzyme that can break down ATP?
ATPase
What are the three methods of energy delivery?
Creatine phosphate
Glycolysis
Oxidative respiration
How does creatine phosphate deliver energy?
In the first few second of exercise it supplies contracting muscles with ATP and enables glycolysis to be initiated
How is glycolysis accomplished in the cytoplasm?
Glycolytic enzymes (phosphofructokinase)
What is AV-O2 difference?
The difference in arterial and venous oxygen concentrations
What is the equation for VO2?
VO2 = Q x (AV-O2)
What does an EEG measure?
Records the pyramidal neurons in the superficial layer of the cortex
What is the order of brain waves from fastest to slowest?
Beta waves - >13 Hz
Alpha waves - 8 -13 Hz
Theta waves - 4 -7.5 Hz
Delta waves - 1 - 3.5 Hz
What is happening when beta waves are observed?
Observed in an awake state, involved in conscious and logical thought, related to problem solving and memory
What is happening when alpha waves are observed?
Promote feelings of relaxation and help us calm down, found in daydreaming, inability to focus and being very relaxed
What is happening when theta waves are being observed?
Helps us improve our intuition and creativity, makes us feel more natural, emotional connection, intuition and relaxation
What is happening when delta waves are being observed?
Found most often in young children = and are associated with the deepest levels of sleep and relaxation, helps us feel rejuvenated and promotes the immune system, natural healing and restorative/deep sleep
What happens in stages 1 - 4 in the sleep cycle?
Stage 1 - more theta activity, loss of alpha
Stage 2 - theta and delta waves’
Stage 3 - higher voltage delta waves
Stage 4 - more than 50% delta slow waves
What happens during REM sleep?
Rapid eye movements, dreaming, loss of muscle tone except for the diaphragm, lasts about 10 minutes per episode, time spent in REM diminishes over time
What are the formed elements of the blood?
Red blood cells, white bloods cells and platelets
What id the primary and other functions of blood?
Primary function is to transport and deliver oxygen and nutrients and remove waste
Other functions include defense/protection and regulation and maintenance of homeostasis
What is the partial pressure of oxygen in arterial blood?
PaO2 = 100mmHg
What is the partial pressure of oxygen in venous blood?
PaO2 = 40mmHg
What is the normal range for blood pH?
7.35 - 7.45