Physiology Final Exam

Question 1

1.Define homeostasis and identify the components of the homeostatic system in a representative system.

Answer 1

Homeostasis-the ability of an organism to maintain a consistent internal environment or “steady state”, in response to changing internal or external conditions. (keeping internal conditions stable)
Stimulus: changes in a variable that is regulated by

Receptor- detects stimulus Ex: sensory neurons in skin, stretch receptors in muscle
Control center- integrates input and changes through the effector Ex: brain spinal cord, endocrine gland
Effector- structure that brings about change to the stimulus ex: muscle or gland

Question 2

1. State the partial pressure of carbon dioxide and oxygen in the alveoli, the arterial and venous blood and the systemic cells.
   Atmosphere:

Answer 2

PO2=159 mmHg
PCO2=.3mmHg

Veins:
PO2=40mmHg
PCO2=45mmHg

Alveoli:
PO2=104mmHg
PCO2=40mmHg

Systemic Cells:
PO2=4ommHg
PCO2=45mmHg

Question 3

2.Define the terms hypoventilation and hyperventilation and explain how they influence the composition of the blood.

Answer 3

Hypoventilation: a reduced minute ventilation (Ve)
resprate x resp depth mL/min→L/min
Where breathing is insufficient to meet the bodies needs: PCO2 is increases

Hyperventilation: Increased minute ventilation, greater then is needed to meet the metabolic demands of the tissue PCO2: decreases

Question 4

4.Identify the structures of the urinary system and describe the general function of each.

Answer 4

Inferior Vena cava kidney renal vein, renal artery, abdominal aorta, ureter, urinary bladder, Urthea

Question 5

Identify the components of a nephron

Answer 5

Renal Corpuscle
-bowman’s capsule
-glomerulus: budle/tuft of capillaries, First site of filtration

Afferent and efferent arterioles are innervated by the SNS

Increase in SNS→ decrease blood flow→ filtering→ urine volume

Afferent Arteriole: blood flow into the glomerulus
E for exit
Efferent arteriole: blood flowing out of the glomerulus
Proximal convoluted Tubule (PCT)
Distal convoluted tubule
Descending and ascending loops
Collecting tubules- branch off
Big duct at the bottom= collecting duct

Question 5

5.Describe the anatomy of the kidney including major structures, blood flow.

Answer 5

Kidney Innervation : Autonomic Nervous System, Sympathetic Nervous system increased activity=decreased blood flow
Renal cortex
renal medulla
renal calyx (minor)
Major calyx
Renal artery
Renal vein

Urinary Bladder:
-somatic nervous system which innervated the external urethral sprinter
-the parasympathetic nervous system innervates the bladder muscles and internal urethral sphincter

Question 6

6.Describe the path urine travels from the renal pelvis to the urethra.

Answer 6

minor calyx→ major calyx→ renal pelvis→ ureter→ urinary bladder→ Urethra

Question 7

9.Give examples of substances: freely filtered, not filtered, and filtered in a limited way.

Answer 7

Not filtered
RBC
WBC
Platelets
Large and small proteins

Freely flitered
Water
Glucose
Amino Acids
Ions
Urea
Some hormones
Vitamins B+C
Ketones
Small amount of proteins

Question 7

8.Describe the three layers that make up the glomerular filtration membrane

Answer 7

Endothelium (blocks formed elements)
Basement membrane (blocks large proteins)
Filtration slits of visceral layer (block small proteins)

Question 8

10.State some of the waste products excreted in urine. State what is reabsorbed and secreted at the PCT, what is reabsorbed at the nephron loop.Describe how sodium and water reabsorption is regulated at the DCT, collecting tubule and collecting duct.

Answer 8

Filtrates- 180L water ions nutrients (glucose) trace proteins

Move from PCT to blood (reabsorbed)
- all nutrients, all proteins, majority water 25% , majority ions 25%.

Moves from blood to PCT (secreted):
-some drugs and nitrogenous waste

Distal convoluted tube (DCT)
Na+ reabsorption is regulated by aldosterone and ANP
Water reabsorption is regulated by aldosterone and ADH

Question 9

10.Define the three general transport processes that occur in the nephron.

Answer 9

Glomerular filtration- first pass filter, mostly for smaller things, the movement of substances form the blood within the glomerulus into the capsular space

Tubular Reabsorption- the movement of substances from the tubular fluid back into the blood like glucose

Tubular secretion- the movement of substances from the blood into the tubular fluid

Question 10

State the normal urine output and the composition of urine

Answer 10

Distal CT→ collecting tubule→ collecting duct→
Volume 1-1.5 L ions, water, some drugs

Question 11

12.Describe the characteristics of normal urine.

Answer 11

Dark urine=dehydration
pale= good hydration

PH=4.5-8
Specific gravity= 1-1.03
Water content= 93-97%
volume= 1-15 L/day
color= pale yellow
odor= variable with composition
protein= trace amounts 5-10 mg/day
blood= none

Question 12

11.Describe how the kidneys regulate blood volume in response to changes in blood osmolarity and blood volume.

Answer 12

What does the Kidney Excrete?
*Some hormones and drugs
*Urea: by product of protein metabolism, if levels in blood get high can create reactive oxygen species (ROS)
*Uric Acid: by product of breakdown of purines (adenine)
*Creatinine: waste product of creatine metabolism

Kidneys Regulate Blood volume
Antidiuretic hormone
Rest: basal (ADH)
Exercise: increase the release of ADH from the post pituitary , decrease urine production
Alcohol: blocks ADH, release increase production of urine
Nighttime/sleep: increased release of ADH

Atrial Natriuretic Peptide- increases blood volume
-stretch of atria causes production and release of ANP in the blood
- ANP→ reduces activity of the sympathetic nervous system
-ANP blocks the ADH release

Aldosterone- increased osmolarity
Low blood pressure in the kidney triggers release of Aldosterone
And causes a reabsorption of sodium on the nephron

Question 13

13.Describe the process of micturition

Answer 13

Increased stretch on the detrusor muscle
Activates parasympathetic nervous system
Contract bladder and Relaxes the internal urethral sphincter
External urethral sphincter is under conscious control (somatic nervous system)

Question 14

14. Describe the general process of erythropoiesis.

Answer 14

Stimulus: decrease O2 content
Receptor: O2 sensing cells in kidney
Control Center: erythropoietin
Effector : bone marrow increase RBC production

Kidney, liver, brain, neurons all produce EPO in response to drop in O2 content mostly kidney then less and less as the list goes on.

Question 15

Identify the functions of the kidney/urinary system.

Answer 15

• Filters the blood and regulates the volume of blood
• Eliminates waste products (Urea and uric acid, creatinine) and biologically active components like hormones and drugs)
• Regulates the level of ions and Acid Base Balance also BP, fluid loss, and the number of red blood cells

Question 16

Describe how ADH triggers the reabsorption of water in nephron.

Answer 16

ADH- causes cell to put a water channel in the membrane (aquaporin)

Question 17

Why does sleep apnea cause increased urine volume.

Answer 17

Sleep apnia- When Co2 levels rise it causes you to gasp for air but if this happens alot you can become desensitized to it
Low PO2 signals PA releases ANP receptor
Increase urine volume because the posterior pituitary gland

The release of atrial natriuretic peptide (ANP), shifts in blood volume, and disrupted sleep patterns.

Question 18

17.List the organs of the GI tract and the accessory digestive organs.

Answer 18

Upper GI Tract
Oral cavity
Pharynx
Esophagus
Stomach
Duodenum (first part small intestine)

Question 19

18.List and describe the six general functions of the digestive system.

Answer 19

Ingestion:introduction of food (solid or liquid) into the oral cavity. First step in digestion and absorption of nutrients.

Motility: the mixing and moving of material through the GI tract. Involves voluntary and involuntary muscle contractions. All along the digestive tract.

Secretion: process of producing and releasing substances that facilitate digestion. Produced by the accessory glands, salivary glands, liver, pancreas.
Digestion: breakdown of ingested food into smaller components that can be absorbed from the GI tract.
Mechanical: breakdown of food into smaller particles, w/o changing the chemical composition.

Chemical: involves specific enzymes that breakdown larger molecules into smaller ones.

Absorption: involves membrane transport of ingested molecules, electrolytes, vitamins, water across the epithelial membrane into the blood or lymph.

Elimination: expulsion of indigestible components through the anal canal.

Question 20

19.Compare long reflexes and short reflexes that regulate the digestive system.

Answer 20

Innervation of the Digestive System
Enteric Nervous System (ENS): array of sensory and motor neurons that extent the entire digestive tract.
Innervated glands and smooth muscle.
Coordinates complex reflexes of mixing and movement of material through the digestive tract.
Can function independently.
Autonomic Nervous System (ANS):
Parasympathetic and sympathetic
Parasympathetic: promotes GI activity, stimulated movement, stimulates secretions, increases blood flow, relaxes GI sphincters.
Sympathetic: opposes GI tract activity, inhibits movement, inhibits secretions, decreases blood flow, contracts sphincters.

Regulation of the Digestive System Nerve reflexes
Reflexes (by ANS or ENS) are initiated in response to receptor input
*Short reflex–local reflex, only involves ENS; coordinate small segments of GI tract
*Long reflex–involves sensory input to CNS and ANS output; coordinate GI tract motility, secretions, and accessory digestive organs.
*Stretch receptors detect stretch in GI tract wall
*Chemoreceptors monitor chemical contents in lumen

Question 21

20.Describe the general features of the GI tract and the process of mixing and propulsion

Answer 21

Tunics of the Abdominal GI Tract
Hollow tube from the esophagus through the large intestine.
Four general layers called tunics

Mucosa: Epithelium: allows for secretion and absorption
Muscularis: layers of smooth muscle, circular layer, and longitudinal layer.

Motility
Mixing: back and forth motion. Mixing waves and segmentation.
Propulsion: Direction movement through the GI Tract, peristalsis: sequential contractions.
bolus=mass of food

Question 22

21.Describe the location and function of the salivary glands and the composition of saliva.

Answer 22

Salivary Glands
Saliva contain water, electrolytes, salivary amylase, mucin and lingual lipase
Parotid: largest, 25-30% of the saliva
Submandibular: floor of the oral cavity and medial to mandible Produces about 60-70% of the saliva
Sublingual: inferior to the tongue, 3-5% of saliva
Mechanical digestion: mashing with jaw/teeth, tongue
chemical digestion- salivary glands, tongue

Question 23

22.Describe the anatomical features of the esophagus that regulate the passage of food into and out of the esophagus.

Answer 23

Digestion in the Esophagus Bolus of food enters the esophagus Entry to the esophagus is controlled by the upper/superior Esophageal sphincter -skeletal muscle Waves of muscle contractions, move the food bolus towards the stomach (peristalsis) Bolus enters the stomach, must pass through lower/inferior esophageal sphincter

Question 24

23.Describe the gross anatomy of the stomach and the two primary functions of the stomach.

Answer 24

Lower Esophageal Sphincter: Regulates the passage-way of food bolus into the stomach Pyloric Sphincter: Regulates the passage of chyme from stomach into the duodenum (small intestine) Gastric folds (rugae): allows the stomach to expand *Bolus mixed with stomach juices becomes chyme* Motility in the stomach: Gastric Mixing and Emptying Gastric Mixing Contraction of smooth muscle in stomach wall mix bolus with gastric secretions from chyme Peristaltic waves result in pressure gradients that move stomach contents toward the pyloric region Gastric Emptying Pressure gradient increases force in pylorus against pyloric sphincter Pyloric sphincter opens and a small volume of chyme enters the duodenum Pyloric sphincter closes and retropulsion occurs

Question 25

24. Briefly describe the hormonal regulation of digestion.

Answer 25

Regulation of the Digestive System: Hormonal control *Several hormones participate in regulation of digestion *Circulating hormones : released in the blood, released by one organ and acts on the same or another organ. *Local hormones: released by cells and acts locally on adjacent cells.

Question 26

25. Identify the organs of the lower GI tract and the accessory digestive organs.

Answer 26

Upper GI Oral cavity Pharynx Esophagus (duodenum) Lower GI Small intestine: three sections diameter> 30’ long Duodenum Jejunum Ileum “Dude Jump In” Large intestine 2- 3 diameter in length Accessory Organs: liver Gallbladder Pancreas

Question 27

26 .Describe the anatomy of the small intestine and how this contributes to its Function.

Answer 27

Large surface area Mucosa Circular folds: slow the movement of chyme. Allow for more time for absorption of nutrientsIntestinal villi, greatly increase the surface area for absorption Multiple layers of smooth muscle that mix and propel the chyme through the small intestine Chyme in small intestine for extended period of time Majority nutrients, water, electrolytes absorbed here Simple columnar cells contain a brush border with different functions metabolism and absorption

Question 28

27.Describe the anatomy of the pancreas and how this contributes to its function.

Answer 28

Duodenum wraps around the head and the tail points laterally Mainly an exocrine gland But also has endocrine functions Endocrine: produces insulin and glucagon 2-3 % cells Into the blood Exocrine:pancreatic juices 98 % cells Into a duct main pancreatic conduct

Question 29

Describe the general structure and function of the liver.

Answer 29

Liver- Second largest organ in the body Right and left are separated by a large ligament. Right is larger than the left Produces bile Produces transport proteins Detoxifies the blood Gallbladder- located posterior to the liver Stores bile Bile helps with the digestion of lipids

Question 30

29.Describe the general structure and functions of the large intestine.

Answer 30

Relatively wide tube, shorter than small intestine Absorbs some water And electrolytes Watery chyme compacted into feces Stores feces until eliminated through defecation Contain gut microbiome Three segments of the large intestine: Cecum, colon and rectum Indigenous microbiota: breakdown carbs, protein, fat Produces CO2 Peristalsis:slow and sluggish Mass movements: powerful contractions, propel fecal matter towards rectum, 2-3 times a day, often after a meal

Question 31

30.Describe the general structure and function of the anal canal.

Answer 31

Anal canal: last few centimeters of large intestine Internal anal sphincter: involuntary smooth muscle at the base External anal sphincter: voluntary skeletal muscle

Question 32

31. Describe the defecation reflex

Answer 32

Rectum contents stimulate baroreceptors in rectal wall Increased nerve signals relayed by sensory neurons to the spinal cord Increased nerve signals relayed along parasympathetic motor neurons Smooth muscle of the sigmoid colon and rectum contract, squeezing the contents, internal anal sphincter relaxes

Question 33

Describe the digestion of carbohydrates.

Answer 33

-Small amount (5%) of chemical digestion, salivary amylase. -Negligible amount digestion by salivary amylase, enzyme is inactivated by low pH -Majority (>90%) of CHO digestion occurs here, pancreatic amylase. -Enzymes in the brush border breakdown disaccharides to monomers. -Negligible amount of CHO digestion In the small intestine: Certain disaccharides require a specific enzyme for digestion. *E.g., lactase digests lactose to glucose and galactose *Reduced amount or lack of lactase = lactose intolerant

Question 34

Describe the digestion of proteins.

Answer 34

No chemical digestion of protein in mouth Chemical digestion of protein begins in the stomach. Pepsinogen is an inactive form of pepsin. Pepsin begins the process of chemical digestion. Low pH in the stomach (~2) activates pepsinogen to pepsin. HCl produced by parietal cell in stomach Start with trypsinogen Then mixes with an enteropeptidase to make trypsin Which either makes chymotrypsinogen then chymotrypsin or procarboxypeptidase to carboxypeptidase

Question 35

34.Describe the digestion of lipids in the small intestine and the role of bile.

Answer 35

-Fat droplet you ingest need to be broken down before they can be absorbed into the body. -fat droplets are composed of many triglyceride molecules -Bile and lipid droplets form micelles Pancreatic lipase breaks down the triglyceride in lipid droplet into monoglyceride (MG) and free fatty acids (FFA). -MG and FFA are taken up into the cell and then repackaged into a large protein covered ball of triglycerides: chylomicrons.Absorbed into the lymphatic system(lacteals) , then eventually dumped into the blood at the superior vena cava - Bile salts emulsify lipid droplets

Question 36

Define the range of GI transit time for the entire GI system

Answer 36

Stomach: 4- 6 hours Small Intestine: at least 3-5 hours but typically 12 hours Large Intestine: 12 - 24 hours average 36 hours Total GI Transit time: normal range 10-72 hours

Question 37

1.Define homeostasis and identify the components of the homeostatic system in a representative system.

Answer 37

Homeostasis-the ability of an organism to maintain a consistent internal environment or “steady state”, in response to changing internal or external conditions. (keeping internal conditions stable) Stimulus: changes in a variable that is regulated by Receptor- detects stimulus Ex: sensory neurons in skin, stretch receptors in muscle Control center- integrates input and changes through the effector Ex: brain spinal cord, endocrine gland Effector- structure that brings about change to the stimulus ex: muscle or gland

Question 38

Define negative and positive feedback.

Answer 38

Negative feedback- resulting action will be in the opposite direction of the stimulus (most common) Positive feedback- stimulus is reinforced

Question 39

Define the following terms:, acid, and base.Define pH and explain the relative pH values of both acids and bases. Acids

Answer 39

Acids- proton donor, dissociate in water forms H+ Strong acid- produce a lot of H+ Bases Bases- proton acceptor Strong bases- dissociate and bind more H+ Weak base- bind less H+ PH- measure relative concentration of H+, units moles/L low PH acidic, high PH basic

Question 40

5.List five important molecules within the body that function primarily in chemical energy exchange and how long that energy source can sustain exercise.

Answer 40

ATP- levels are maintained relatively consistent in the cell as the use is balanced by production 2 to 3 seconds worth of energy duration from ATP PCr- phosphocreatine concentrations 4 to 5 times higher than ATP levels sustain energy for 10-15s seconds Glycogen- 1-2 hours energy source can sustain energy Lipids- 2-4% of muscle is lipids, you can go for 3-7 days using fat Protein- 10-15% of calories coming from protein, long duration relatively high intensity

Question 41

.Explain how the H+ gradient is used to produce ATP and what is the name of the specific enzyme?

Answer 41

Movement of H+ is used to pump synthesize ATP through the enzyme ATPsynthase

Question 42

1.Describe passive transport and distinguish between simple and facilitated diffusion.

Answer 42

Passive Membrane transport Does not require external energy, substances move down their concentration gradient Include osmosis and diffusion Simple Diffusion of a solute, system moves toward equilibrium Oxygen, carbon dioxide, and nonpolar molecules use simple diffusion Facilitated diffusion: channel mediated- doors always open moves charged particles down their concentration gradient through water filled channels Na+ high outside low indie, K high inside low outside

Question 43

2.Describe active transport and distinguish between primary and secondary active transport.

Answer 43

Active transport- ions or small molecules moved against their concentration gradient Ex: Na+, K+, Glucose Primary active transport: ion pumps or ion exchangers - ATP is the energy source -ATPases -Ca is low in the cell and high inside the cell Sodium potassium pump/ATPase Energy from splitting ATP moves sodium and potassium against their concentration gradient Secondary active transport -Move glucose from low to high concentration -Energy comes from sodium gradient Symporter: substances move in the same direction Antiporter- substances move in opposite direction

Question 44

3.Describe how keratinocytes change as they mature.

Answer 44

-As they mature that produce more and more keratin, Cell full of keratin, organelles and nucleus die

Question 45

4.Explain what causes differences in skin color. Color from hemoglobin, melanin, and carotene

Answer 45

Hemoglobin -blood binds oxygen in the blood - gives skin sort of red color, oxygen -binding protein in red blood cells -Bright red color upon binding oxygen, gives blood vessles in dermis a reddish tint -Fair skinned individuals more visible if blood vessels dilate Myoglobin-binds oxygen in the CELLS like muscle cells

Question 46

5.Define a motor unit and describe the differences between small and large motor units and the muscles they innervate.

Answer 46

Motor unit: an alpha motor neuron and all muscle fibers it innervates Small motor units: less than 5 muscle fibers, precise movements, eyes, hands Large motor units: thousands of muscle fibers, large amount of force but little precision. Thigh muscles Large/many fibers is used for picking up heavier things

Question 47

Describe the different types of muscle contractions.

Answer 47

Isometric contraction- generates force but no length change example is something being too heavy to lift Isotonic Contraction- skeletal muscle contraction results in movement Concentric- muscle shortening (curl dumbbell towards the body) Eccentric- muscle lengthens

Question 48

8.Identify the three functional categories of neurons and where they are Primary located.

Answer 48

Sensory neuron:afferent, conduct sensory input towards the CNS Motor neuron:efferent, conduct motor output away from the CNS Interneuron: are completely w/in the CNS, facilitate communication between sensory and motor, most abundant type of neuron SAME DAVE Sensory Afferent Motor Efferent Dorsal/back Afferent Ventral/front Efferent

Question 49

9.Briefly describe the physiological events that occur at the different segments of the neuron.

Answer 49

Receptive segment - binding of neurotransmitter released from presynaptic neurons: production of graded potentials Presynaptic neuron Post synaptic neuron Graded potential Initial segment- VGNa and VGK channels summation of graded potentials; initiation of action potential Conductive segment-send action potential down the axon Transmissive segment- VGCa++ channels ATPase action potential causes release of neurotransmitter

Question 50

1.Name the major gyri, sulci, and fissure of the brain.

Answer 50

Central sulcus- separates anterior and posterior (yellow and blue) Lateral sulcus- on lateral (separates red from yellow and blue) Medial- Separates right hemisphere from the left when looking top down

Question 51

2.Describe the concept of cerebral lateralization.

Answer 51

1.Some localization but difficult to assign precise function of specific regions. 2.Cerebral hemispheres receive sensory form and project motor commands to the opposite side of the body. 3.Mirror images, some specialization. Left: categorical- analytical and sequential processing science and math Right: representation: musical and artistic side shapes and colors

Question 52

3.Describe the general functions of the 5 lobes of the Cerebrum

Answer 52

Frontal lobe- decision making, concentration, planning, personality, verbal communication ,Motor association Area Parietal Lobe- Somatosensory area Primary somatosensory cortex- general sensory input, sensory input from the skin, joints Temporal Lobe–Primary Auditory Cortex, Primary Olfactory Cortex, Involved in processing hearing, smell and some vision, Stores auditory and visual memories Occipital Lobe– processing visual inputs and coordinating eye movements Insular Lobe-Sensory Association Area

Question 53

4.Describe the general structure and functions of parasympathetic and sympathetic divisions of the autonomic nervous system.

Answer 53

Parasympathetic- originates in preganglionic neurons in brain stem S2-S4 segments of the spinal cord , functions to bring body to homeostasis in condition of “rest and digest” Sympathetic - Preganglionic neurons originate in T1-L2 segments of the spinal cord, Functions to bring body to homeostasis in conditions of fight or flight

Question 54

5.Describe the effects of dual innervation and provide an example of opposing/antagonistic activity.

Answer 54

Parasympathetic- decrease heart rate Decrease force of contraction Sympathetic- increasing heart rate and increasing force of contraction

Question 55

6.Describe the general function of sensory receptors as transducers.

Answer 55

Detect Stimuli: external and internal environments Each type of receptor responds best to a specific type of stimulus Light for eye receptors; sound for ear receptors Convert Stimuli:Transducers—change stimulus energy into electrical signal 1.Receptors have a RMP 2.Modality- gated channels that respond to their type of stimulus

Question 56

7.Describe the concept of adaptation and how it applies to Tonic versus Phasic Receptors.

Answer 56

Adaptation—decreased sensitivity to continuous stimulus tonic receptors: limited adaptation: respond continuously *For example, head position receptors in inner ear; all pain receptors Phasic receptors: adapt rapidly: only respond to new stimuli *For example, pressure receptors

Question 57

8.Identify the major endocrine glands, the hormones they secrete, and the location of these glands in the body.

Answer 57

Pituitary gland- many hormones, base of the brain, considered the master gland Pineal- secretes melatonin, posterior base of the brain, and regulates sleep wake cycle/circadian rhythms Thyroid- releases thyroid hormones primarily T3 and T4 and calcitonin, located anterior aspect of the through/trachea Parathyroid- posterior aspect of the thyroid gland, parathyroid hormone is secretes Adrenal- superior aspect of the kidney contains two regions the adrenal cortex (outer region) and the adrenal medulla (inner core)

Question 58

9.Explain the three reflex mechanisms for regulating the secretion of hormones and examples of each.

Answer 58

Hormonal- hormone release is triggered by other hormone Humoral- nutrients, blood, or ions trigger change Nervous system- Nervous system triggers hormone release

Question 59

10.Define up-regulation and down- regulation and the potential causes of each.

Answer 59

Up-regulation:increase sensitivity exercise and insulin sensitivity (acute) Down- regulation- reduce sensitivity beta receptors on the heart with aging (chronic)

Question 60

1.List the three components of a centrifuged blood sample.

Answer 60

Erythrocytes (44% of whole volume) red blood cells bottom of the tube Buffy coat (<1% of the whole blood) Plasma (55% of whole blood) - albumins most common protein in the plasma

Question 61

2.Describe the general process of erythropoiesis.

Answer 61

Produces RBC Start: Stimulus: hypoxia due to decreased RBC count decreased availability of O2 to blood, or increased tissue demands for O2 Reduces O2 levels in blood Kidney (and liver to a smaller extent) releases erythropoietin Erythropoietin stimulates red bone marrow Enhanced erythropoiesis increases RBC Increases O2 carrying ability of blood

Question 62

3.Identify the features of the right and left side of the heart and the role these features play in determining the functioning of the heart

Answer 62

Right atrium: receiving chambers right ventricle: pumping chambers larger and more muscular lungs/pulmonary circulation peripheral/systemic circulation base :top of heart broader and wider Apex: inferior bottom of the triangle Left ventricle is the larges and most muscular chamber LORD

Question 63

4.Describe the flow of blood through the heart

Answer 63

RA→ TVC→ RV→ PSL→ pulmonary trunk→ → pulmonary circulation→ pulmonary vein→LA→ BCV→LV→ AS→ Aorta→ systemic circulation

Question 64

5.Describe the components of the electrical conduction system of the heart.

Answer 64

Pathway of electrical activity Starts in sinoatrial (SA) node- pacemaker of the heart 60-100 bpm Atrioventricular node- internal 40-60 bpm, when it gets to the AV node it slows down a little and is delayed Atrioventricular bundle/ bundle of his and septum but moves faster through the AV bundles Branches more to purkinje fibers (20-40 bpm) Toward the apex of the heart Coordinated response

Question 65

6.Define the terms stroke volume, heart rate, and cardiac output and know the average resting values.

Answer 65

Cardiac Output: CO (L/min) = SV (mL/b) * HR (b/min) . ~ 5 L/min at rest Heart rate: (HR b/min): resting 60–80 b/min(max 220–age). Stroke Volume: (SV mL/b): average 70 mL/b(range 50-110mL/b).

Question 66

7.Describe the cardiac cycle and define the two phases of the cardiac cycle, systole and diastole.

Answer 66

Systolic phases of the cardiac cycle Isovolumetric contraction phase Ejection phase Diastolic Phase of the cardiac cycle- gets much slower during exercise Isovolumetric Relaxation- all valves are closed and blood is not flowing Rapid filling Phase- AV valve opens and blood flows from high pressure to low pressure atria→ ventricle Atrial Contraction Phase

Question 67

1.Describe the factors that influence stroke volume.

Answer 67

Factors That Influence Stroke Volume -Major factor that determine stroke volume is venous return. -Venous return determines preload -Amount of blood in the heart at the end of diastole = EDV -Increased venous return, increased Preload, Increased stroke volume

Question 68

2.Describe the two subcellular mechanisms responsible for the Frank -Starling Law of the Heart.

Answer 68

Frank -Starling Law of The Heart- (increased Stroke Volume by increase Venous Return) EDV increases, greater stretch of heart wall results in the thick and thin filaments moving closer together. Increased sensitivity to calcium = more force Heart contracts more forcefully when filled with more blood so SV increases

Question 68

4.Describe how the body responds to an acute decrease or increase in blood pressure.

Answer 68

Regulation of blood pressure homeostasis Sensory input Receptor- baroreceptors/ stretch receptors (tonic receptors) To the control center (brain stem/medulla oblongata_ To the effectors (systemic blood vessels) Or the heart (conduction system and cardiac tissue) Then to motor output

Question 69

5.Distinguish between central and peripheral receptors.

Answer 69

Central chemoreceptors -Increase in PCO2 (H+) Medulla Peripheral chemoreceptors- in the aortic arch and carotid sinus, increase PCO2, H+, decrease PO2 Central Thermoreceptors Hypothalamus- respond to changes in temperature Peripheral Thermoreceptors Skin

Question 69

7.List the three types of cells found in the alveoli, and describe the function of each.

Answer 69

Alveolar Type 1 cells: most abundant, make up the internal surface of the alveolus simple squamous, ideal for diffusion Alveolar Type II cells: less common, much smaller, simple cuboidal, produce and secrete surfactant. Alveolar Macrophages: mobile scavengers, engulf foreign material, dust, bacteria etc.

Question 70

6.Describe the control of breathing.

Answer 70

Control center respiratory center(brain stem) Pons- rate and depth of breathing Medulla- inspiration, expiration Motor output, motor nerves (somatic nervous system) diaphragm, external intercostals