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Human Biosciences > Human Physiology > Flashcards

Human Physiology Flashcards

1
Q

Temperature homeostasis?

A

Body temp falls:
Blood vessels constrict
Sweat glands don’t secrete fluid
Shivering occurs

Body temps increase:
Blood vessels dilate
Sweat glands secrete fluid
Shivering doesn’t occur

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2
Q

What is glucose homeostasis?

A

High blood glucose:
Pancreases releases insulin

Low blood glucose:
Pancrease releases glucagon

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3
Q

What is respiration in pulmonary level and cellular level?

A

Process of ventilation
Exchange of O2 and CO2 in the lungs

O2 utilisation and CO2 production

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4
Q

Main purposes of respiratory system?

A

Gas exchange

Acid-base regulation

Homeostatic regulation of body pH

Vocalisation

Protection from inhaled pathogens and irritating substances

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5
Q

What’s pulmonary ventilation?

A

Moving air in and out of lungs

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6
Q

What’s external respiration?

A

Gas exchange between lungs and blood

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7
Q

What’s internal respiration?

A

Gas exchange between systemic blood vessels and tissue

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8
Q

What’s in conducting zone and what does it do?

A

Moves air into respiratory zone
Humidifies, warms and filters

Trachea
Bronchial tree
Terminal bronchioles

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9
Q

What does the respiratory zone do and what’s in it?

A

Exchange of gases

Respiratory bronchioles
Alveolar ducts
Aveolar sacs

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10
Q

What cleans alveolus?

A

Alveolar macrophage

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11
Q

What do type 1 and type 11 alveolar cells do?

A

Type 1 aids permeability

Type 11 makes surfactant to stop them sticking together

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12
Q

What Boyle’s law?

A

Pressure of a gas in a closed container is inversely proportional to the volume of the container at a constant temperature

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13
Q

What is atmospheric pressure?

A

760 mmHg or 1 ATM

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14
Q

Process of breathing in (exact opposite occurs for exhalation)?

A

Increase size of lungs

Volume increases

Decreased alveoli pressure

Air rushes into lungs

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15
Q

What does diaphragm and external intercostals do in active inhalation?

A

Diaphragm:
Flattens
Due to phrenic nerves
Lowers dome when contracted

External intercostals:
Contraction elevates ribs
Up and outwards
Accessory muscles aid for deep forceful inhalation

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16
Q

What occurs in exhalation at rest?

A

Pressure lungs greater than atmospheric

Passive process due to elastic recoil and relaxation of diaphragm and external intercostals

Thoracic cavity reduces

External intercostal muscles relax

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17
Q

What is minute ventilation?

A

Amount per minute

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18
Q

What is tidal volume?

A

Amount per breath

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19
Q

Breathing frequency?

A

Number of breaths

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20
Q

How to work out alveolar ventilation?

A

0.7 x tidal volume

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21
Q

How to work out dead space ventilation?

A

0.3 x tidal volume

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22
Q

What is inspiratory reserve volume?

A

Maximum volume of air that can be inhaled (from top of tidal volume on graph)

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23
Q

What is Expiratory reserve capacity?

A

Maximum volume of air that can be voluntarily exhaled (from bottom of tidal volume on graph)

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24
Q

What is residual volume?

A

Volume of air remaining in the lungs after maximal exhalation

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25
Q

What is vital capacity?

A

Maximum volume that can be inhaled and exhaled (IRV + Tidal volume + ERV)

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26
Q

What is FRC functional residual capacity?

A

Volume of air present in the lungs at the end of passive expiration (ERV + RV)

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27
Q

What is total lung capacity?

A

Around 6 litres

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28
Q

How do we breathe?

A

Respiratory control centres within our brain

Medulla oblongata:
Rhythmicity area-
Ventral group
Dorsal group

Pons:
Pneumotaxic
Apneustic area

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29
Q

What does pneumotaxic exactly do?

A

Superior portion of pons

Teams with MRA to set rhythm of breathing

Inhibitory pulses prevent lungs from becoming to full with air

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30
Q

What does Apneustic area do?

A

Coordinates transition between inspiration and expiration

Stimulates inspiratory area to prolong inspiration and slow rate of breathing

Only occur when pneumotaxic area is inactive

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31
Q

What dictates how we breath?

A

Voluntary control:
Motor cortex

Involuntary control:
Feedback

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32
Q

Ventilation loops?

A

Sensors, to central controller to effectors back to sensors

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33
Q

What do central chemoreceptors do?

A

Elevated PCO2 or pH results in hyperventilation

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34
Q

What are the peripheral chemoreceptors?

A

Cartoid body
(CN9)

Aortic body
(CN10)

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35
Q

What are the respiratory stretch receptors?

A

Activated by overinflation of the lungs

Inhibitory discharge sent to inspiratory area

Reduced discharge from RSR

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36
Q

2 other types of receptors?

A

Irritant receptors (mechanoreceptors) and peripheral proprioceptors (muscles tendons joints)

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37
Q

How do gases move into blood from alveoli?

A

Diffusion

Pressure gradient, not a concentration gradient

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38
Q

What is Dalton’s law?

A

Total pressure of a mixture is equal to the sum of the partial pressures of the individual gases in a mixture

So partial pressure = % concentration ( as decimal) x total pressure of mixture

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39
Q

What gas is most abundant and second most in the atmosphere?

A

Nitrogen, second is Oxygen

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40
Q

Henry’s law?

A

When a mixture of gas is in contact with a liquid each gas dissolves in the liquid in proportion to it’s partial pressure and solubility until equilibrium is achieved and the gas partial pressures are equal in both locations

Solubility is constant

Pressure gradient is critical, gases diffuse from high pressures to low pressures

So more gas molecules are soluble at a higher pressure

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41
Q

Fick’s law of diffusion?

A

V Gas = A x D x (P1 -P2) / T

V gas = rate of diffusion
A = tissue area
D = Diffusion coefficient of gas
P1 - P2 = Difference in partial pressures
T = Tissue thickness
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42
Q

What damages alveoli?

A

COPD (Chronic Obstructive Pulmonary Disease) and smoking

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43
Q

Features of capillaries?

A

Single cell layer so very thin

Slower blood flow in capillary bed providing more time for diffusion

Largest surface area

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44
Q

Types of blood samples?

A

Capillary:
Fingertip
Ear

Venous:
Venipuncture
Cannula

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45
Q

What do you need for capillary blood collection?

A

Disinfectant, steile swabs, sterile gloves, a safety lancet, appropriate sample container, plasters, waste container

Capillaries should be horizontal or slightly inclined

Sample container needs to be inverted after blood collected

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46
Q

Components of blood?

A

Plasma:
Mainly water
Some protein
Little nutrients and hormones

Buffy coat:
White blood cells and platelets

Red blood cels
Haematocrit
Females 37-47%
Males 42-52%

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47
Q

Typres of oxygen transport?

A

1% dissolved in plasma:

Dissolved O2 establishes the pressure of oxygen in blood which regulates breathing and determines loading of haemoglobin

99% combined with haemoglobin = oxyhaemoglobin

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48
Q

Features of a RBC and Haemoglobin?

A

Bioconcave shape

4 iron molecules per haemoglobin, 1 molecule per iron group
High affinity for O2

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49
Q

Describe the oxyhemoglobin dissociation curve?

A

Higher Po2 = Higher % O2 saturation

Acidity
Pco2
2,3-BPG (2,3-DPG) Temperature
All affect unloading

Acidosis occurs when acidity increases, affinity of Hb decreases, more O2 delivered to acidic sites

When Pco2 increases, affinity of Hb decreases, the harder the tissue is working more O2 is released

BPG is formed during glycolysis and helps to unload O2 by binding with Hb

As temperature increases, there is higher unloading
Affinity of Hb decreases, so more O2 delivered to warmed up muscles

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50
Q

Features of myoglobin?

A

Iron-containing globular protein in skeletal and cardiac muscle

1 iron atom

Even higher affinity than Hb, even at low Po2

Transfers O2 from cell membrane to mitochondria/muscles

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51
Q

Features of Cytochrome C Oxidase?

A

O2 binds to harm a3 group

Higher affinity than myoglobin

O2 is then the final acceptor in the ETC

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52
Q

CO2 combines with? forming what equation? What does chloride shift do?

A

CO2 + H2O (catalysed by carbonic enzyme) = H2CO3 = H+. + HCO3-

Replace HCO3- with Cl-, maintains balance of charge

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52
Q

How is CO2 transported in blood?

A

Dissolved
Carbamino compounds
Bicarbonate ions

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52
Q

Decreases in O2 carrying capacity?

A

Hypobaric environment
Concentration of gases in mixture stays the same

But there is Reduction in total pressure decreases the partial pressure of O2

Less molecules of Oxygen

Anaemia:
Reduces RBC’s and iron and therefore O2 carrying capacity

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53
Q

Illegal ways of increasing O2 in blood?

A

Withdraw blood and store in fridge, training recovers RBC mass, inject own blood back in overall RBC mass increases

Inject EPO

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56
Q

Purpose of the cardiovascular system?

A

Controls blood transport around the body:
O2 and nutrients to tissues
Removal of CO2 and wastes from tissues
Transport of hormones

Regulation of body temp

Immune function

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57
Q

What is the CV system composed of?

A

Heart
Arteries and arterioles
Capillaries
Veins and venules

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58
Q

Describe the cardiac cycle?

A

Diastole:
Relaxation phase
Filling

Pressure in ventricles is low
Atria fills with blood
Atria pressure > ventricular pressure
AV valves open

Systole:
Contraction phase
Ejection of blood

Pressure in ventricles rises
Blood will be ejected in pulmonary and systemic circulation once ventricular pressure is larger than aortic pressure as semi lunar valves open

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59
Q

What does an electrocardiogram do?

A

Composite record of electrical events

12 leads

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60
Q

Electrical components of the heart?

A 
Sinoatrial node:
Anterior internal tract
Middle internal tract
Posterior internal tract
Bachmann's bundle

Atrioventricular node:
Bundle brunch
Conduction pathways

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61
Q

3 recognisable waves in an ECG?

A

P wave- small bump before QRS complex, atrial depolarisation

QRS complex - down, up, down, ventricular depolarisation

T wave - small bump after QRS complex = ventricular repolarisation

Abnormalities indicate disease

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62
Q

What is Lub dub sound created from?

A

Mitral valve closes

Aortic valve closes

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63
Q

Resting values of BPM in trained and untrained, and in Bradycardia and Tachycardia?

A

70 BPM males and females untrained

50 BPM trained males

55 BPM trained females

Bradycardia is smaller than 60 BPM

Tachycardia resting is larger than 100 BPM

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64
Q

2 important factors of vessel radius?

A

Vasconstriction:
Radius decrease
Resistance to flow increases

Vasodilation:
Radius increases
Resistance to flow decreases

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65
Q

What location of the brain can influence breathing?

A

Medulla oblongata

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66
Q

Features of the parasympathetic nervous system?

A

Activates vagus nerve

Parasympathtic neurones release acetylcholine

Inhibits SA and AV discharge delaying the rate of sinus discharge

So heart rate decreases

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67
Q

What does the sympathetic nervous system do?

A

Actiaves sympathetic cardiac accelerator

CA nerves release adrenaline and noradrenaline from adrenergic fibres

Positive chrontropic and inotropic effects though beta-adrenergic receptors

Heart rate increases

Ventricular contractility increases

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68
Q

Who discovered the cell?

A

Robert Hooke, looking at thin slice of cork, witnessed cells

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69
Q

Differences of prokaryote cell to a eukaryote?

A

Pro:

Lack a distinct nucleus bound by a membrane

lack membrane bound organelles such as mitochondria and chloroplasts

Single circular DNA and some small DNA called plasmids in cytoplasm

Eu:

Have a nucleus

Contain membrane bound organelles

Mitochondria for respiration

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70
Q

What is the cytosol?

A

The cytoplasm but if the organelles were removed

Location of chemical reactions

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71
Q

What is the nucleus?

A

Contains DNA, condensed and orgaisned with proteins as chromatin

Surrounded by nuclear envelope

Contains nuclear pores, regulated by a protein structure - the nuclear pore complex

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72
Q

What is the nucleolus?

A

Spherical body of the nucleus that becomes enlarged during protein synthesis

Contains DNA templates for rRNA transcribed by RNA polymerase 1

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73
Q

Central dogma?

A

DNA to RNA to Protein

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74
Q

Features of mitochondria?

A

Allow oxidative phosphorylation:

Occurs in a membrane bound electron transport system

Creates ATP using a H+ gradient

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75
Q

What is endosymbiotic theory?

A

Mitochondria were primitive bacterial cells

Over millions of years mitochondria and eukaryotes become mutually beneficial

This is now a permanent dependent relationship

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76
Q

Features of mitochondrial DNA?

A

They have their own DNA

Circular

Zygote derives from mtDNA from the ovum - passed on through mother

Encodes for 37 genes

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77
Q

Features of the endoplasmic reticulum>

A

Forms an interconnected network of tubules, vesicles and cistern within cells

Site of protein synthesis and packaging of cell chemicals into transport vesicles

Smooth:
Takes part in synthesis of membrane and lipid steroids

Small portion of ER

Rough:

Studded with ribosomes

Where protein synthesis occurs

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78
Q

What does Golgi apparatus do?

A

Stacks of membrane bound cistern located between the ER and cell surface

Mainly devoted to processing the proteins synthesised in the RER

Vesicular enzymes modify and transports molecules in cells

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79
Q

Features of ribosomes?

A

Made up of protein and rRNA

The ribosomes clamps over the tRNAs and mRNAs to make new protein

A site receives new tRNA

P site receives peptide bearing tRNA after peptide bond forms

E site is where tRNAs exit

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80
Q

4 major proteolytic systems?

A

Lysosomes
ATP - dependent ubiquitin proteasome - protein breakdown
Calpains
Caspases

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81
Q

What are lysosomes?

A

Created by the addition of hydrolytic enzymes to early endoscopes from the Golgi appartus

Work best at low pH - so they pump H+ ions into themselves from cytosol

They create a space where the cell can digest molecules

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82
Q

features of ATP - dependent ubiquitin proteasome - protein breakdown ?

A

Breakdown tagged cellular proteins

Essential part of normal cell turnover

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83
Q

Features of calpains and caspases?

A

More specific protein degradation - for fine tuning

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84
Q

What are peroxisomes?

A

membrane bound organelle sacs

Oxidation reactions produce Hydrogen peroxide, they contain catalase converting it to H2O or use it to oxidise another organic compound

Uric acid, amino acids and fatty acids are all broken down via these oxidation reactions

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85
Q

Features of the cytoskeleton?

A

Extensive network of protein fibres

Functions in:
Providing mechanical strength
Locomotion, remodelling
Chromosome seperation in mitosis and meiosis
Intracellular transport of organelles
Cellular signalling

Microfilaments - Linear polymers of actin subunits which resist compressive and tensile forces

Microtubules - conveyer belts inside the cells, they move vesicles, granules, organelles like mitochondria and chromosomes via special attachment proteins. Made up of linear polymers of tubular

Intermediate filaments - withstand mechanical stress

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86
Q

What are focal adhesions?

A

Attachment complexes anchor contractile filaments to cell membrane

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87
Q

What is part of the extracellular matrix?

A

Proteins exocytosed in to the extracellular space - often referred to as connective tissue

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88
Q

What is endocytosis?

A

Take up

Cell membrane invaginate, pinches in, creates vesicle enclosing contents

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89
Q

What is exocytosis?

A

Release

Membrane vesicle fuses with cell membrane, releases enclosed material to extracellular space

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90
Q

Example of exocytosis?

A

Collagen synthesis

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91
Q

Features of cell membrane (fluid mosaic model)?

A

Hydrophilic (polar) heads on outside, Hydrophobic (non-polar) fatty acid tails on inside

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92
Q

Features of crossing the membrane?

A

Osmosis- aquaporins

Simple diffusion - no channels

Facilitated diffusion - assisted via protein channels

Active transport pumps and carriers - requires energy, primary and secondary transport

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93
Q

What is a solvent?

A

The liquid which contains a solute

94
Q

Solute?

A

Substance that is put into the solvent

95
Q

Hypertonic fluid?

A

High concentration of solutes , so water moves from inside to outside of cell

96
Q

Isotonic fluid?

A

Equal solute concentrator. inside and out so no mocement

97
Q

Feature of hypotonic?

A

Lower concentration of solutes, so water moves from outside to inside cell

98
Q

Which molecules can simply diffuse?

A

Small non polar molecules such as oxygen

99
Q

Molecules that are transpired in facilitated diffusion?

A

Polar molecules and charged ions, as can’t get past polar fatty acid tails

100
Q

What is secondary active transport (coupled transport)?

A

Ions are moved across the membrane against the concentration gradient due to pumps

Then another molecule can join with the ion which will return down the electrochemical gradient

101
Q

What creates the resting membrane potential?

A

SOPI pumps

102
Q

What is a signal transduction pathway?

A

Series of molecular steps that describe the signal being transmitted through the cell

103
Q

What is thermoregulation?

A

The ability of an organism to keep its body temperature within certain boundaries

104
Q

What does humans being homeotherms mean?

A

Constant internal body temperature regardless of external stimuli

105
Q

What are endotherms?

A

Generate heat internally

Maintain high basal heart production

eg. mouse

106
Q

What are ectotherms?

A

Depend on external heat sources

Temperature changes with the environment

107
Q

How hot are humans?

A

Internal core body temp = 36.6-37.5 degrees

Optimal function = 36.5-40.0 degrees

108
Q

When does hypothermia occur and symptoms?

A

When internal core temperature drops bellow 35 degrees

109
Q

When does hyperthermia occur?

A

Internal core temperature above 38 degrees

Results in heat exhaustion (lots of sweating) or heat stroke (no sweating)

Above 42 will cause damage to cells

110
Q

Which part of the brain controls body temperature?

A

Hypothalamus

111
Q

Sites in which core body temperature can be measured?

A 
Hypothalamus
Oesophagus
Rectum
Intestinal 
Oral under tongue
Ear drum
112
Q

What does the body priorities in having the correct optimal temperature in cold or hot conditions?

A

Areas near your internal organs and brain

113
Q

What is specific heat capacity?

A

Amount of energy required to raise the temperature of a given substance by 1 degree

Different substances have different values

Water = 4.186
Human body tissue = change in temperature

114
Q

The law of conservation of energy?

A

Energy can neither be created nor destroyed - it can only be transformed from one state to another

115
Q

How can heat be generated?

A

Liberate chemical energy in food we eat

Resynthesize ATP, process inefficient as energy is not equal to ATP resynthesis

116
Q

Difference between voluntary and involuntary heat production?

A

Voluntary:
Exercise
70-80% EE appears as heat

Involuntary:
Shivering 
Action of hormones
Thyroxine
Catecholamines
117
Q

Examples of external heat gain?

A 
Sky thermal radiation
Solar radiation
Reflected
Air température and humidity
Ground thermal radiation
118
Q

Examples of heat loss?

A

Conduction
Convection
Radiation
Swear evaporation

119
Q

Heat transfer is always from?

A

Higher to lower temperatures

120
Q

What is heat transferred through?

A

Electromagnetic waves

121
Q

What is conduction?

A

Heat transfer from the body of an object with direct contact

122
Q

What is convection?

A

Heat transfer to or from air or water

123
Q

What is evaporation?

A

Vaporisation of sweat from water to vapour

124
Q

Features of sweating?

A

Released from sweat glands

Stimulated by sympathetic nervous system

Increased SNS when exercising, or nervous

125
Q

Factors influencing evaporation?

A

Temperature
Convection currents
Skin exposure

126
Q

Equation for sweat loss?

A

= Change in mass + fluid intake - urine

127
Q

Sweat rate depends on?

A 
Body size
Absolute VO2
Aerobic fitness
Heat acclimatisation 
Environment
128
Q

Areas of the body with greater heat loss?

A

The skull
The groin
The armpits
Extremities

129
Q

How does hyperthermia improve sprint/power performance?

A

Decreased resistance of muscles/joints

Faster nerve conduction velocity

Improvement in muscle contractile elements

Faster metabolic rate

Q10 effect

Increased SNS activity

However it impairs endurance performance

130
Q

What is central fatigue?

A

Brain stops sending out the neural impulses to contract the muscles

131
Q

Importance of hydration?

A

Cool drinks can lower temperature

Cool drinks are absorbed faster in the GI tract

132
Q

Total body water definition?

A

Fluid that occupies intra-cellular and extra-cellular spaces = 0.6 L/Kg = 60% of body mass

133
Q

Intra-Cellular volume?

A

Fluid within tissue cells = 0.3L/kg = 40% of body mass

134
Q

Extra-cellular volume?

A

All fluids outside of cells = 0.2L/Kg (20%) of body mass

135
Q

What is interstitial fluid volume?

A

Located in spaces between tissue cells = 16% of body mass

136
Q

What is plasma volume?

A

Liquid portion of blood = 4% of body mass

137
Q

Describe the 2 semi-permeable membranes that separate, ICF, interstitial fluid and plasma?

A

Plasma membrane separates ICF from surrounding interstitial fluid

Blood vessel wall (capillaries) divide interstitial fluid from plasma

138
Q

WHat’s a solvent?

A

Substance that dissolves a solute

139
Q

What’s a solute?

A

A substance dissolved in a solvent

140
Q

Describe measuring body water status?

A

Measures body’s electrolyte-water balance

Osmolality - number of osmoses of solute per kg of solution

Osmolarity - number of osmoses of solute per litre of solution

Determined on a plasma, saliva or urine sample

141
Q

What is euhydration?

A

State of normal body water level

142
Q

What’s hypohydration?

A

State of reduced body water level

143
Q

What is hyper hydration?

A

State of elevated body water level

144
Q

Electrolyte functions?

A

Control osmosis of water between body fluid compartments

Helps maintain the acid-base balance

Carry electrical current]]

Serve as cofactors

145
Q

In the extra cellular fluid which is most abundant cation and anion?

A 
Na+ - 
Muscle contraction
Impulse transmission
Fluid and electrolyte balance
Main electrolyte lost in sweat

Cl -
Regulates osmotic pressure
Forms HCl

146
Q

In the intra cellular fluid which is most abundant cation and anion?

A 
K+
Resting membrane potential
Action potentials
Maintains intracellular volume
Regulation of pH

Anions are proteins and phosphates

147
Q

Describe how sodium interaction with body water regulation?

A

Sodium is the only cation to exert significant osmotic pressure

Sodium ions leaking into cells and being pumped out against their electrochemical gradient

Osmoreceptors stimulated, then either increased ADH released, increased thirst, decreased urinary water loss

Or reduced ADH released, decreased thirst, increased urinary water loss

148
Q

Features of ADH?

A

Hypothalamus tells the posterior gland to release it

This is stimulated by haemoconcentration during exercise, increase in plasma osmolality, or decrease in plasma volume

ADH promotes water retention in the kidney in an effort to dilute plasma electrolyte concentrations

149
Q

Features of aldosterone?

A

Mineralcorticoid hormone

Released from adrenal cortex

Secretion is stimulated by (renin-angiotensin mechanism) :
Decreased plasma sodium
Decreased blood volume
Decreased pressure
Increased plasma potassium concentration

Promotes renal reabsorption of sodium, causing the body to retain sodium

Systemic aldosterone release reaches kidney, increased sodium reabsorption in distal convoluted tubule and the collecting duct

Net effect is increased fluid retention

150
Q

Look at past papers to see if long question on renin-angiotensin mechanism)

A

if so add all steps from water lecture

151
Q

Features of Hyponatremia?

A

When Na+ concentrations fall bellow normal range due to excessive fluid intake, or lots of blood loss

lots of negative symptoms

152
Q

Cellular consequences of dehydration?

A

Loss of solutes / reduced blood volume

Causes changes in osmotic pressure

Cells lose water and shrink due to osmosis

153
Q

Advantages of isotonic (balanced), hypotonic (low concentration of solutes), and hypertonic solutions (high concentration of solutes)?

A

Isotonic:
Easily absorbed and quickly leaves the stomach

Hypotonic:
Less easily absorbed, more useful in hot weather

hypertonic:
Take too long to leave stomach, digestion problems, cause dehydration

154
Q

Effects of alcohol?

A

Increased rate of urination
Lower fluid retention
Reduced plasma volume

155
Q

What’s successful compensation?

A

When Homeostasis has been re-established

156
Q

What is failure to compensate?

A

Negative effects occurring due to failure to re-establish homeostasis

157
Q

What’s the endocrine system?

A

Glands that release hormones into the blood to be carried to distant organs

Example is skeletal muscle

158
Q

4 keys way hormones can communicate?

A

Endocrine - blood to distant site

Autocrine - acts back on the cell that produced it

Paracrine - acts directly on a nearby cell

Juxtacrine - communication between 2 connecting cells which requires physical contact between them

159
Q

3 ways endocrine glands are stimulated to release hormones?

A

Humoral stimuli - changes in composition of blood

Hormonal - due to other hormones

neural stimuli - nerve fibres stimulate the release

160
Q

Do hormones affect all cells?

A

No only target cells, which has the specific receptors

161
Q

What does the magnitude of hormone effect depend on?

A

Number of target receptors (they are continuously synthesised and degraded, so number can vary over short time periods)
Concentration of hormone
Affinity of receptor for hormone
Influence of other hormones

162
Q

2 main catergories of hormones?

A

Steroid:
Lipid soluble - synthesized from cholesterol
Circulate in blood with bound protein (classifying them as inactive at the point)
Diffuse into the cell

Non steroid:
Water soluble
high molecular weight so can’t diffuse across cell membrane
So act via binding to receptors on plasma membrane = first messenger

163
Q

What is signal transduction?

A

the process by which extracellular signals are communicated into a cell to affect function

first messenger followed by a second messenger, series of enzymes altered, altering cell function

164
Q

Positive and negative feedback loop?

A

Positive - effect is amplified

Negative - effect is nullified

165
Q

Features of the pituraity gland?

A

In brain and has posterior and anterior lobes both under control from hypothalamic hormones

Anterior:
Receives hypothalamic hormones via vessels, which stimulates further hormone release by pituitary

Posterior:
Stores hormones made by hypothalamic neutrons and releases into circulation (so does not synthesise hormones)

Main ones are ADH and oxytocin (uterus contraction and milk ejection during lactation)

166
Q

Difference between the nervous system and the endocrine system?

A

Nervous system is more short term and very specific and uses neurotransmitters

Endocrins system is more long term, more general and uses hormones

167
Q

Describe the action of a steroid hormone?

A

Diffuse into the cell

Bind to specific receptor located in either the cytoplasm or nucleus

Hormone - receptor complex activates gene expression

Protein synthesis is induced

168
Q

Features of the pineal gland?

A

Produces melatonin, which is suppressed by light and stimulated by dark so most active at night time

Modulates sleep patterns in circadian rhythms

169
Q

Features of the thyroid gland?

A

Butterfly shaped and located in the neck, inferior to the larynx

Secretes the hormones Triiodothyronine and Thyroxine

Involved primarily in tissue development and growth as well as macronutrient metabolism

Hormone production is stimulated by anterior pituitary releasing thyroid stimulating hormone

170
Q

Features of the parathyroid gland?

A

4 glands located at posterior of thyroid gland, which produce PTH

PTH is most important regulator of serum Ca(2+) levels, as stimulates reabsorption at kidneys, and in bone

171
Q

2 functions of the pancreas?

A

Exocrine function:
Secretes enzymes to digest carbohydrates

Endocrine function:
Secretes substances to regulate blood glucose levels

172
Q

Describe the islets of langerhans in the pancreas?

A

Alpha cells produce glucagon that increases blood glucose

Beta cells produce insulin that decreases blood glucose

Deta cells - produce gastrin and somatostatin that regulates alpha and beta cells

F cells - produce pancreatic polypeptide that regulates metabolism

173
Q

Features of the adrenal glands?

A

Pair of glands that sit on the top of the kidneys

Each gland has an outer adrenal cortex and an inner adrenal medulla

Outer adrenal cortex:
produces steroid hormones

Inner adrenal medulla:
Acts as part of sympathetic nervous system and releases epinephrine (adrenaline) and norepinephrine in fight or flight response

174
Q

Describe the 3 main dysfunctions that can occur to the hormonal system?

A

Abnormal hormone receptor function / levels

Altered intracellular response to the hormone receptor complex

Hyper or hypo secretion of hormones by glands

175
Q

Where are alpha receptors found and what are they stimulated by?

A

Mostly found in sympathetic organs / tissues

Norepinephrine and epinephrine

176
Q

Where are beta receptors found?

A

Located on membranes of many organs such as muscles lungs heart and liver

just epinephrine

177
Q

4 hormones that work to increase the amount of circulating glucose?

A

Glucagon, epinephrine, norepinephrine and cortisol

Epinephrine and norepinephrine stimulate more glucagon to be released and less insulin

178
Q

Difference between type 1 diabetes and type 2?

A

Type 1:
Results from the body’s failure to produce insulin

Onset typically in early childhood

Type 11:

Insulin resistance - cells fail to use insulin properly

Onset typically in adulthood

179
Q

Symptoms of type 1 diabetes?

A

Weight loss as loss CHO causes excess use of fat for weight loss, and the inhibitory effects of insulin on breakdown is lost

Ketoacidosis occurs so ketones are released into blood by the liver due to lots of fats being used as an energy source, lots of dehydration as kidneys try to remove them in urine and by vomitting as well. Can go in coma

180
Q

Symtoms of type 2 diabetes?

A

Vascular complications

Nerve damage

181
Q

What does the CNS include?

A

Brain and spinal cord

182
Q

What odoes the peripheral nervous system contain?

A

Cranial nerves, 12 pairs

Spinal nerves, 31 pairs

183
Q

4 lobes of the cerebrum?

A

Frontal

Parietal

Temporal

Occipital

google function and location

184
Q

What is the cerebellum?

A

Coordinates movement by cerebral cortex

185
Q

Parts of the brain in sensory integration and homeostasis regulation?

A

Diencephalon - thalamus, hypothalamus, pituitary gland

186
Q

What is the brain stem?

A

Connects brain to spinal cord

CV and respiratory control

187
Q

What the device called that can stimulate different part of the brain?

A

TMS (transcranial magnetic stimulation)

188
Q

What are afferent nerves?

A

Sensory neurons

Impulses from receptors to CNS

189
Q

Features of efferent nerves?

A

Motor neurons

Impulses from CNS to effectors

190
Q

What are baroreceptor?

A

Stretch receptors, sensitive to changes in blood pressure

191
Q

What are chemorecptors?

A

chemical receptors

192
Q

What are mechanoreceptors?

A

Detect muscle tension and length

193
Q

What are metaboreceptors?

A

Skeletal muscle metabolites

194
Q

What are nociceptors?

A

Pain receptors

195
Q

What are interneurons?

A

When a shortcut is needed, for example pain

Pass afferent transmission to efferent transmission without need to involve brain, so it’s just spinal cord

So Spinal cord can control simple motor reflexes

Where brain controls more complex and sometimes subconscious motor reactions

196
Q

Describe what the interneuron does in the myotatic/stretch reflex (hammer on knee)?

A

Stimulate muscles to make knee flex as well as stopping other muscles preventing this

so they analyse the sensory information, store some aspects and make decisions

197
Q

What’s in the autonomic nervous system?

A

Involunatry responses

SNS and PNS

198
Q

What’s in the somatic nervous system?

A

Motor nuerons

Skeletal muscle function

199
Q

Tissues of the nervous system?

A

Neurones

Neuroglia - protective and supporting, don’t conduct nerve impulses

Oligodendrocytes - support cells in CNS

Astrocytes - regulate electrical transmission in the brain

200
Q

Features of motor units?

A

2 components - alpha motor neurones and muscle fibres stimulated by them

3 types are slow (type 1), fatigue resistant (type 11a), fast fatiguing (type 11x)

One muscle neurones innervates each single muscle cell

201
Q

Anatomy of a neurone?

A

Dendrites- pick up signals

Axon hillock - nerve impulse generated

Axon carries nerve impulse away from cell body

Synapses = contact point

Myelinated means they have a myelin sheath which are fatty and insulating

Nodes of ranvier are breaks in the myelin sheath - increases the transmission of impulses, as they jump between them

202
Q

3 nerve fibre groups?

A

A - (Alpha, bet, gamma) all are myelinated

B - moderate myelination

C - unmylinated

203
Q

How to increase velocity of an action potential?

A

Amount of myelination, more = faster

Axon diameter - faster as diameter increases

Temperature, faster as temperature increases

204
Q

3 structural classifications of neurones?

A

Multipolar - cell body in dendrites
Unipolar - cell body at the side
Bipolar - cell body in the middle

205
Q

Action potential definition?

A

A sequence of rapidly occurring events that reverse the membrane potential and then restore to a resting state

206
Q

What is the membrane potential?

A

Difference in amount of electrical charge inside and outside the cell.

207
Q

What creates the resting membrane potential in cells?

A

SOPI pumps create a -70mV inside the cell

208
Q

Describe the steps of an action potential?

A

Depolarisation occurs when sufficient stimulus depolarises the cell, voltage gated Na+ open and sodium floods in at-55mv

Repolarisation - returning to resting membrane potential, Na+ channels close, K+ leaves the cell due to voltage hated K+ channels

Hyperpolarisation - caused by delay in closing of voltage gated K+ channels

209
Q

What does graded potential mean?

A

That an action does happen or doesn’t, no in-between

210
Q

What are synapses?

A

Gaps between neurones so they have to communicate via electricity or chemicals via the synaptic cleft

211
Q

2 types of postsynaptic potentials?

A

EPSP - excitatory postsynaptic potential

IPSP - inhibitory postsynaptic potential

212
Q

What’s spatial summation?

A

Summation of effectors of neurotransmitters released from several end bulbs onto one neuron

213
Q

What’s temporal summation?

A

Summation of effect of neurotransmitters released from 2 more in rapid succession

214
Q

What’s the refractory period?

A

Excitable membrane needs recovery, during this period it can’t be excited again

there is absolute period where nothing can stimulate it, and a relative period where only a large stimulus could evoke an action potential

215
Q

3 types of muscle?

A

Smooth
Cardiac
Skeletal

216
Q

Features of smooth muscle?

A 
Fusiform shaped (tapering at both ends)
Involuntary contractions (slow wave motions)
Not striated with only one, centrally located nucleus

Primary functions - digestion, Breathing and circulation

217
Q

Features of cardiac muscle?

A

Has cardiomyocytes

Narrow and shorter than skeletal

One nucleus, many mitochondria

Intercalated discs support synchronised contraction of cardiac tissue

218
Q

Features of skeletal muscle?

A

Elongated muscle cells

Myocytes (long structures)

Multi-nucleated

Striated

Banded pattern (proteins)

219
Q

Describe the thick filament and thin filament in a myofibril (muscle cell)?

A 
Thick:
Mainly Myosin  (bit of titin)

Thin:
Actin
Troponin
Tropomyosin

220
Q

What does Titin do?

A

Inside the thick filament
Keep thick and thin filaments aligned
Resist muscle from overstitching
Recoil muscle to resting length after stretching

221
Q

What’s in the toponym complex?

A

Tropomyosin
Calcium
Actin

222
Q

What does Nebulin do?

A

Achors Actin to Z disk

223
Q

What does dystrophin do?

A

Anchors actin to sarcolemma via a protein complex

224
Q

What’s muscular dystrophy?

A

Weakening and breakdown of skeletal muscle

225
Q

Does the I band contain myosin?

A

NO

226
Q

What happens to bands during contraction?

A

H band dissapears
I band narrows
A band stays the same
Z line move closer together

227
Q

What’s Henneman’s size principle?

A

Motor units are activated in a preset sequence depending on motor neurone size

1 then 11a then 11x

Recruitment is based on force not on velocity

228
Q

More features of type 1 fibres?

A

Slow contraction sped

Adaped for aerobic respiration by having high capillary density, and high myoglobin content

High mitochondrial density and content of oxidative enzymes

229
Q

More features of type 11 fibres?

A

Fast contraction speed

Adapted for anaerobic respiration

Less blood supply myoglobin and mitchdondria

High content of glycogen and glycolytic enzymes

230
Q

Features of transverse tubules and steps after?

A

Dihydropyridine receptor - voltage gated calcium channel

Ryanodine receptor - responsible for release of Ca2+ from sarcoplasmic reticulum

Then Ca2+ are mechanically coupled to Actin, by binding to troponin on the thin filament, shifts tropomyosin off myosin dining sites, enables myosin to bind to actin

231
Q

Features of Calsequestrin?

A

Glycoprotein

Moderate affinity and high capacity for Ca2+

Allows large quantities of Ca2+ to be stored in sarcoplasmic reticulum

Human Biosciences (69 decks)

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