Physiology 生理学重点

Define the following terms and list the example
1Internal environment: All cells live in the same environment ——the extracelluar fluid. In the extracellular fluid are the ions and nutrients needed by the cell to maintain cell life. For this reason, the environment fluid is also called the internal environment.
2Homestasis: can maintain the internal environment stable which means the physical and chemical properties of extracelluar fluid only change in a limited range called normal physiological range.
3 Negative feedback: A change in a condition leads to responses from the effectors which counteracts that change.
4 Positive feedback:A change in a condition leads to responses from the effectors which amplifies.
5 simple diffusion: lipid-soluble substances or small polar molecules diffusion directly through the interstices of the lipid bilayer.
Example: oxygen, nitrogen, carbon dioxide, alcohols, H2O, urea
6 Facilitated diffusion via ion channel: the channel facilitates diffusion of ions to the other side, three types: voltage-gated channel, chemical-gated channel and mechanically-gated channel. Ions(Na+，K+, Cl+, Ca+), H2O.
Voltage-gated Channel
电压门控
Chemical-gated Channel
化学门控
Mechanically-gated Channel
机械门控
7 Facilitated diffusion via carrier: the carrier (transporter) facilitates diffusion of some lipid-in soluble moleclues to the other side. Glucose, amino acid
8 Primary active transport: making directly use of energy derived from ATP to transport the ions across the cell membrane against their concentration gradients. Na+-K+ pump, calcium pump, proton pump
9 Secondary active transport: The ion gradients established by primary active transport permits the transport of other substances against their concentration gradients. Na+-glucose pump, Na+-amino pump.
10 Resting potential: A potential difference across the membrane of the cell negative relative to the outside of the cell
11 polarization: A state in which the resting potential is positive on the outside and negative on the inside
12 K+ equilibrium potential: “balance” means that the electrical force that results form the build-up of ionic charge, and which impedes outward diffusion, increases until it is equal in magnitude but opposite in direction to the tendency for outward diffusive movement of potassium. This balance point is an equilibrium potential as the net transmembrane flux of K+ is zero.
13 action potential: Some of the cells (excitable cells) are capable to rapidly reverse their resting membrane potential from negative resting values to slightly positive values. This transient and rapid change in membrane potential is called
an action potential.
14 Threshold potential:is the critical level to which the membrane potential must be depolarization in order to initiate an action potential. Threshold intensity/value: the minimal stimulus that produces excitation.
15 saltatory conduction: the action potential are conducted from node to node
16 excitability: the property of a cell that enables to react (generate AP) to stimulation, such as the ability of a nerve or muscle cell to react an electric stimulus.
17 absolute refractory period: the period during which a second action potential cannot be elicited, even with a strong stimulus.
18 end plate potential: the depolarizations of end plate membrane caused by Ach binding to N2-Ach receptors in the neuromuscular junction. It is a local potential.
Ach门控通道阻断剂---α银环蛇毒
Na+电压门控通道阻断剂---河豚毒TTX
19 cross-bridge cycling: the muscle contractile process in which the cross-bridge binds to actin, twists and resets.
20 excutation-contraction coupling: is the muscle physiological process of converting an electrical stimulus(action potential) to a mechanical response(muscle contraction).
21 isometric contraction: tension increases but the length of the muscle does not change when a mucle contracts.
22 isotonic contraction: tension remains constant but the muscle shortens when
a mucle contracts.
23 afterload: afterload is the load that is given to the muscle after the beginning of the contraction.
24 preload: preload is the load that is given to the muscle before the beginning of the contraction. Preload=initial length
25 hematocrit:the volume of red blood cell(erythrocytes) as a percentage of centrifuged whole blood.
26 erythrocyte sedimentation rate:the distance that red blood cell settle in a tube of blood in one hour
27 hemostasis: small damaged blood vessel stop bleeding after a few minute.
28 blood coagulation: is the process that blood change from the sol to illiquid gel state.
29 blood group: a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells
30 extrinsic pathway: the coagulation pathway initiated by FII exposed to blood which comes from outside the blood.
31 intrinsic pathway: gradually clot the blood completely depending on the coagulation factors in the blood.
32 stroke volume:volume of blood pumped out of each ventricle per beat. SV=EDV-ESV. At rest: SV:~70ml
33 cardiac output：the total volume of blood pumped by each ventricle per
minute. At rest: 5L/min(4.5-6.0L/min)
34 ejection fraction (EF):Stroke volume as a percentage of end-diastolic ventricles. EF = SV/EDV╳100% . 60%
35 cardiac index:cardiac output per square meter of body surface area.
3.0~3.5L/(min·m2)
36 cardiac reserve：the maximum percentage that the cardiac output can increase above the normal level.
37 Frank-starling mechanism: The intrinsic ability of the heart to adapt to increasing volumes of inflowing blood through increasing ventricular end-diastole volume.9
38 heterometric regulation: the regulation of stroke volume as a result of changes in cardiac muscle fiber length is called heterometric regulation.
39 homometric regulation:：regulate the force of contraction without a change in muscle length
40 cardiac cycle: The cardiac events that occur from beginning of one heart beat to the beginning of the next are called the cardiac cycle.
Systole, diastole.
41 end-systolic volume:As the ventricles empty during systole, the volume decreases about 70ml.The remaining volume in each ventricle,about 50ml,is called the end-systolic volume.
42 end-diastolic volume: During diastole, filling of the ventricles increases the volume of each ventricle to about 130ml.This volume is called the End-diastolic
volume.
心动周期中的几个“最”
心室容积最低：减慢射血期末，等容舒张期,
心室容积最大：心房收缩期末,等容收缩期
室内压最高：快速射血期末
43 premature systole: a contraction of the heart prior to the time that normal contraction would have been expected
44 compensatory pause:the pause between the extra beat and the next normal beat is slightly longer than the usual beat interval, which is called compensatory pause.
Premature systole is generally followed by a so-called conmpensatory pause, because the heart is still in the absolute refractory period of the extrasystole when the excitatory impulse from the SA node arrives.
45 effective refractory period:the duration from the beining of phase 0 to -60mv of repolarization fails to produce action potential to any stimulus, no matter how strong. This duration is called ERP. In ERP, the excitability is almost zero.
46 atrioventricular delay: The atrial muscle are separated from those of ventricles by a fibrous tissue ring. The AV node is normally the only conducting pathway between the atrial and ventricles. Because conduction in the AV node is slow, a delay of about 0.1s occours before excitation spread to the ventricles.
47 Electrocardiogram (ECG) 心电图
The electrocardiograph is a device to record the electrical signals produced by
the heart by placing electrodes on the surface of the skin. The recording obtained is called the electrocardiogram (ECG).
48 systolic pressure:the maximum arterial pressure reached during peak ventricular ejection.
49 diastolic pressure:the minimum arterial pressure just before ventricular ejection begins.
50 pulse pressure: the difference between SP(systolic pressure) and DP(diastolic pressure)
51 mean arterial pressure: the average pressure in the cardiac cycle(=DP+1/3PP)
52 central venous pressure(CVP)pressure of blood in the thoracic vena cava and the right atrium.正常值：4-12cmH2O
CVP ＞16cmH2O
⚫(1) heart failure
⚫(2) massive transfusion of blood
53 venous return:refers to the flow of blood from the periphery back to the right atrium
54 mcrocirculation:capillary blood circulation between the arteriole and venule
55 respiration:The gas exchange process between organization and environment is named respiration.
56 surface tension:Tension of a liquid's surface. Due to the forces of attraction between molecules
Answer the questions
1 Regulation of body function:
Nervous regulation
Humoral regulation
Autoregulation
2 Describe the physiological role of sodium pump:
1 maintaining the Na+ and K+ gradients across the cell membrane, which is the basi to form bioelectricity.
2 maintain the high concentration of K+ inside the cell, which is needed by the cell metabolism.
3 controlling cell volume and osmotic pressure
4 providing energy for secondary active transport
5 partly responsible for establishing a negative electrical potential inside the cell.
3 Factors affecting resting potential
1 K+ concentration gradient.
K+ concentration outside the membrane↑→RP↓
2 membrane permeability to K+ and Na+
More permeable to K+ →RP↑
More permeable to Na+ →the RP↓
3 the activity of Na+—K+ pump
Hypopotassemia血钾过低→RP上升hyperpotassemia 过高→RP下降
4 All-or-nothing principle
1 stimulus must exceed threshold stimulus to trigger AP
2 the amplitude of an AP is independent of the intensity of stimulus that produced it.
3 either they occur fully or they do not occur at all
5 Describe the ionic mechanism of AP
1 change in electrochemical driving force
2 change in membrane permeability
6 Compare the properties of action potential with the local potential
7 second messenger: cAMP, DG(DAG), IP3 cGMP Ca2+
8 properties of action potential (AP)
1AP ia all-or-none
2AP propagates without decrement
3Discharge in form of impulse: unfused(because of refractory period)
9 describe neuromuscular transmission
Depolarization of prejunctional membrane make the voltage-gated calcium
channel open. Then the calcium enter into motor nerve ending. Calcium can promote the exocytosis of synaptic vesicle and Ach release. The Ach can activate N2-Ach receptor channel which can make the N2-Ach receptor cation channel open. Endplate membrane increase the permeability for sodium and potassium.(mianly sodium internal flow). Then endplate membrane deploarize which activates voltage-gated sodium channel. Finally skeletal muscle generate action potential.
10 describe excitation coupling proceeds
1. Spread of the Action Potential to the Interior of the Muscle Fiber by Way of T Tubules
2. This depolarisation activates L-type calcium channels
3. This activates RyR （calcium release channel）via foot processes
4. As the RyRs open, calcium is released from the SR into the cytoplasm.
5. The calcium binds to Troponin C by the actin filaments, to allow cross-bridge cycling, producing force and motion
6. The SR calcium pump actively pumps calcium back into the SR. As calcium declines back to resting levels, the force declines and relaxation occur
11 影响肌肉收缩的四大因素
1 preload
2 afterload
3 contractility
4 summation
12 Crystalloid Osmotic Pressure 晶体渗透压
◼ Pressure generated by all crystal substances, particularly NaCl.
◼ maintaining fluid balance across cell membranes and the normal cell volume ◼ =interstitial fluid
Colloid Osmotic Pressure 胶体渗透压
◼ Osmotic pressure generated by plasma proteins, particularly albumin.
◼ maintaining fluid balance across capillaries and the normal blood volume ◼>interstitial fluid
13 physiological properties of RBC
1 plastic deformation
2 suspension stability : erythrocyte sedimentation rate(the distance that red blood cell
3 osmotic fragility settle in a tube of blood in one hour)
Rouleaux formation →ESR↑
14function of RBC biconcave discs
1 Transport of O
2 (98.5%) and CO2
2 Buffering
KHCO3/H2CO3、KHb/HHb、KHbO2/HHbO2、K2HPO4/KH2PO4
15 production of RBC (erythropoiesis)
◼ Site: bone marrow
◼ Nutritional Requirements for Erythropoiesis: Iron and protein
◼ Maturation of Red Blood Cells: Vitamin B12 (requirement of intrinsic factor)
and folic acid ◼ Regulation of Erythropoiesis：EPO
Deficiencies of these factors lead to characteristic anemias（贫血）
红细胞生成的调节因子：
1 Intrinsic factor, 分泌：由壁细胞分泌的糖蛋白。

作用：促进VitB12的吸收。

Function: promote the absorption of Vitamin B12
Deficiencies of Vitamin B12，Folic Acid, or intrinsic factor lead to Megaloblastic Anemia.
2 erythropoietin, EPO
Function of the erythropoietin mechanism to increase production of red blood cells when tissue oxygenation decreases.
Deficiency of EPO → renal anemia
15physiological properties of platelets
1 adhesion Platelets adhere to the vessel wall at the site of injury
2 release TXA2, ADP, Serotonin, Fibrinogen, Thrombospondin
3 aggregation Platelets adhere to one another
Two phases: 1st reversible phase, 2nd irreversible phase
Inducers of plate aggregation: ADP, collagen, thrombin, TXA2,
4 contraction
5 absorption
16 describe the process in hemostasis
1.Vascular spasm
2.Formation of a platelet plug
3.Blood coagulation (clotting)
The role of platelets in hemostasis
o Release of vasoconstricting substances
o Formation of the "platelet plug"
o Promotion of blood clotting
o Clot retraction
17 list the three essential steps of coagulation
(1)In response to rupture of the vessel, a complex cascade of chemical reactions occurs in the blood involving more than a dozen coagulation factors. The net result is formation of a complex of activated substances collectively called prothrombin activator （凝血酶原酶复合物）.
(2)The prothrombin activator catalyzes conversion of prothrombin into thrombin.
(3) The thrombin acts as an enzyme to convert fibrinogen into fibrin fibers that enmesh platelets, blood cells, and plasma to form the clot.
18 describe the guideline of blood transfusion
1. Ensuring that transfusion recipients (受血者）and donors（供血者）have compatible ABO blood group. Blood typing + Cross-match test
2. For an Rh negative mother or a person who needed repeated blood transfusions，ensuring that transfusion recipients and donors have compatible Rh blood group
19 ABO antibody
（1）Natural antibody：IgM, not pass placenta 胎盘.
（2）Immune antibody：IgG，pass placenta-hemolysis neonatorum
20 Role of atria and ventricles during each cardiac cycle
◼ Atria──primer pump
◼ Ventricles──major source of power
21 effect of heart rate on duration of cardiac cycle.
The heart rate increasing will lead to reducing the cardiac cycle. The period of systole and diastole both decrease.
22 evaluation of heart pumping
1 stroke volume
2 ejection fraction
3cardiac output
4 cardiac index
5 cardiac reserve
23 factors controlling cardiac output
1 preload and heterometric regulation
2 afterload
3 myocardial contractility
4 heart rate
24 Factors affecting preload(end-diastolic volume):
➢venous return 静脉回心血量
-ventricular filling duration：HR
-Velocity of venous return
-ventricular diastolic function
-ventricular compliance 心室顺应性
-pressure in the pericardial cavity（心包腔）
➢remanent blood volume after injection
-blood pressure
-ventricular contractivity
25 significance of Frank-Starling law
-Keep the balance between stroke volume and venous return
- accurately regulate the minor change of stroke volume, such as alteration of position or blood pressure
26 heart sounds caused by closure of valves.
The first heart sound (S1) :
◼ low in pitch and relatively long-lasting “lub”
◼ at the start of systole
◼ caused by closure of the A-V valves.
The second heart sound (S2) :
◼ Shorter,high-pitcher “dup”
◼ at the the start of diastole
◼ aortic and pulmonary valves close
27 What cause the cardiac output increase during exercise
健康人长跑时，交感神经兴奋，四肢骨骼肌交替性舒缩活动增强，有利于机体通过提高心肌收缩能力，增加前负荷，加快心率，增加心输出量。

28
1 ventricular systole:
（1）Period of isovolumic contraction
（2）Period of ventricular ejection
1）Period of rapid ejection 快速射血期:
2）Period of reduced ejection 减慢射血期:
2 ventricular diastole:
（1）Period of isovolumic relaxation
（2）Filling of the ventricles
1）Period of rapid filling 快速充盈期
2）Period of reduced filling 减慢充盈期
3）Atrial systole
29 spread of cardiac excitation
SA node →Atrium →AV node →Bundle of His →Right and left bundle branch →Purkinje fibers →Ventricle。

30 Transmembrane potential of ventricular cells
Resting Potential: -90 mV
Action Potential
◼ Phase 0: Depolarization
◼ Phase 1: Early phase of rapid repolarization
◼ Phase 2: Plateau
◼ Phase 3: Late phase of rapid repolarization
◼ Phase 4: Resting phase
▪Phase 0: rapid depolarization and the overshoot
Threshold potential (-70mV)
Opening of voltage-gated Na+ channels→ rapid influx of Na+
Voltaged-gated Na+ channels open for only a few ms and then abruptly close.▪ Phase 1 Early phase of rapid repolarization
K+ efflux（Ito, transient outwark current）
activated at –20 mV
opening for 5~10 ms
▪ Phase 2 ：the prolonged plateau lasts for about 150ms.
Inward current → outward curent
(Ca2+) ← K+
▪ Phase 3：Late phase of rapid repolarization
Inactivation of Ca2+ channel
Outward K+ current dominates(IK, IK1)
▪ Phase 4: resting stage
钠钾泵，Na+-Ca2+ exchange, Ca2+pump
31 The significance of long refractory period
◼The long refractory period means that cardiac muscle cannot be restimulated until contraction is almost over
◼ This makes summation & tetanus of cardiac muscle impossible
32 Significance of “Phase 2 plateau”
◼ The major characteristic of ventricular muscle AP different from skeletal muscle ◼ Cause the longer refractory period of ventricular muscle
◼ L-Ca 2+ channels open contribute to contraction of ventricular muscle
◼ The target of many factors such as neurotransmitters,chemical factors,and drug.
33 Significance of AV nodal delay
◼ The atria contract about 0.1s ahead of ventricular contraction
◼ This delay allows time for the atria to empty their blood into the ventricles before ventricular contraction begins.
34 Describe the factors affecting autorhythmicity
▪ The velocity （slope）of phase 4 spontaneous depolarization
▪ Maximal repolarization potential
▪ Threshold potential
35 Describe the factors affecting conductivity
➢Structural factors
◼ Diameter of cardiac cells
◼ Gap junctions at Intercalated disk
➢Physiological factors
◼ The velocity and amplitude of phase 0 depolarization
◼ Excitability of adjacent region
36 Describe the characteristics of contractivity in cardiac muscle
1.Summation & tetanus(强直收缩）of cardiac muscle is impossible
2.Skeletl muscle is voluntary muscle, but the cardiac muscle is self-excitation.
3.Skeletal muscle observe size muscle, but the cardiac muscle contracts stimultaneously as a syncytium.
4.Cardiac muscle have high [Ca2+ ]0-dependent.
37 Describe the waves of the ECG
◼ P wave: atrial depolarization
◼ QRS complex: ventricular depolarization
◼ T wave: ventricular repolarization
38 Compare the action potentials in ventricular muscle with those in skeletal muscle
The action potential in skeletal muscle don’t have plateau. The refractory period of ventricle muscle is much longer than that for the skeletal muscle.
39 Compare the action potentials in ventricular muscle with those in autorhythmic cell
40 physiological properties of cardiac cells
◼ Excitability
◼ Conductivity
◼ Autorhythmicity
◼ Contractility
Working cell：Excitability、Conductivity、Contractility
Autorhythmic cell：Autorhythmicity 、Excitability、Conductivity
The mechanisms of SA node to control latent pacemakers
•Capture 抢先占领
•Overdrive suppression 超速驱动压抑
41 describe the formation of blood pressure
Blood pressure means the force exerted by the blood against any unit area of the vessel wall.
➢Precondition: Sufficient Blood filling in the vessels Mean circulatory filling pressure *: 7 mmHg
➢Condition:
a) Heart ejection: Energy supply
b) Peripheral resistance: maintain blood pressure
➢Regulation: large Arterial elasticity
42 list the factors affecting blood pressure
A. Stroke Volume （每搏输出量）↑ ：
Systolic Pressure ↑↑, Diastolic Pressure ↑, Pulse Pressure ↑, MAP ↑
B. Heart Rate （心率）↑:
Diastolic Pressure ↑↑, Systolic Pressure ↑, Pulse Pressure ↓
C. Peripheral Resistance （外周血管阻力）↑：
Diastolic Pressure ↑↑，Systolic Pressure ↑, Pulse Pressure ↓ , MAP ↑
D. Artery elasticity （动脉弹性）↓:
Systolic Pressure ↑, Diastolic Pressure ↓, Pulse Pressure ↑(e.g. aged person’s arteriosclerosis, 动脉硬化)
E. Circulation volume/vessels capacity↓:
Mean circulatory filling pressure↓blood pressure↓
43 list the factors affecting venous return
1、Mean circulatory filling pressure体循环平均充盈压：正比
2、Cardiac contraction（心泵）.正比
3、Muscle contraction. （肌肉泵）：直立步行
4、Respiratory activity （呼吸泵）吸气时，胸腔容积增大，负压加大，使胸腔内的大静脉和右心房扩张，回心血量增加
5、Change of body position(重力作用）：卧位→立位，回心血量↓
44 List the three pathways of microcirculation, and describe the significances of them.
1 circuitous channel (Nutritional channel)
2 Thoroughfare channel
3 arteriovenous shunt (A-V shunt)
Significance: 1"Nutrient pathway ', the main site of substance exchange
2 promote venous return blood flow, a small amount of exchange.
3 Radiation heat dissipation, regulating body temperature.
45 List the 4 primary forces determining fluid movement across the capillary
1 capillary pressure
2 plasma colloid osmotic pressure
3 interstitisl fluid pressure
4 interstitial fluid colloid osmotic pressure
46 List the factors affecting formation of interstitial fluid
⚫ capillary pressure
⚫ plasma colloid pressure
⚫ capillary permeability
⚫ Lymphatic obstruction (as occurs in filariasis)
47 the role of the vagus and sympathetic nerves on heart
Resting: increased vagus nerves activity
Effect of increased parasympathetic and decreased sympathetic activity on heart and blood pressure will reduce the heart rate, which lowers cardiac output and lowers blood pressure
Exercise: increased sympathetic activity
Effect of increased sympathetic activity on heart on heart and blood pressure will increase heart rate and contractility, which can higher cardiac output and increase blood pressure.
48 the effect of sympathetic vasoconstrictor nerve on the blood vessel
调节外周阻力及血压、血流量
交感缩血管纤维兴奋：-血流阻力↑ ，血压↑，局部血流量↓ -毛细血管前阻力↑ /毛细血管后阻力→毛细血管血压↓ ，组织液生成↓ -容量血管收缩，静脉回流量↑
49 The process of baroreceptor reflex in carotid sinus and aortic arch and the properties and significance.
Process: A rise in arterial pressure stretches the baroreceptors and causes them to transmit signals into the central nervous system. “Feedback” signals are then
sent back through the autonomic nervous system to the circulation to reduce arterial pressure downward toward the normal level.
Feature of baroreceptor reflex :
-Negative feedback
-Dual directional regulation
-Rapid, short-term regulation
Significance: Maintaining relatively constant arterial pressure, reducing the variation in arterial pressure
50 Physiological effects of angiotensin II
-Constricts resistance vessels
–Acts upon the adrenal cortex to release aldosterone醛固酮
–Stimulates the release of vasopressin血管加压素
–Facilitates norepinephrine release from sympathetic nerve endings
–Stimulates thirst centers within the brain。