sem 1 exam Flashcards
how scientists investigate
literature review: reviewing past discoveries
observation: information gathered using senses and instruments that enhance senses
classifying: placing things in group because of similarities in characteristics
experimentation: designed to support or disprove a hypothesis
steps to scientific method
- recognise a problem and make question
- collect info regarding to problem
- make hypothesis
- test hypothesis using experiment
- collect data
- draw conclusion on whether hypothesis was proved or disproved
if it was disproved, make new hypothesis
if new question arise from conclusions, then begin whole procedure again
ethical considerations
safety: should be risk fro participants and investigators
ethics: a set of moral principles held by majority
- voluntary participation
- informed consent
- no risk of harm
- Confidentially
- anonymity
cell membrane
outer boundary of cell, made up of a double layer of lips (phospholipid bi layer)
separates the cell from neighbouring cells and external environment. Determines which substances get into or out of the cell
cytoplasm
within the cell membrane. Thick fluid within cell membrane and all structures suspended in it it is more jelly like than cytoskeleton.
cytoplasm is responsible for giving a cell its shape. It helps to fill out the cell and keeps organelles in their place
cytosol: liquid part of cytoplasm, 75-90% water with dissolved substances. salts and. carbohydrates are dissolved, but proteins and fats don’t dissolve (suspended)
nucleus
Central region of the cell. Separated from cytoplasm by a nuclear membrane. DNA and nucleolus are suspended in nuclearplasm.
contains genetic information, 23 pairs of chromosomes. Nuclear membrane has gaps known as pores which large molecules can pass through. Nucleolus makes ribosomal RNA which makes ribosomes
ribosomes
free inside cytoplasm or bonded to endoplasmic reticulum. Very large spherical organelles found in all living cells.
Amino acids are joined together at the ribosomes to make proteins, does RNA translation. Found on their own in cytoplasm or attached to endoplasmic reticulum
endoplasmic reticulum
attached to the nucleus. Pairs of parallel membranes extending through cytoplasm and connecting cell membrane to nuclear membrane, some have ribosomes attached. Provides the surface in which chemical reactions can occur. Channels between paired membranes are used for storage or transport of materials. Rough ER is where proteins are made
Golgi body
free in cytoplasm. Flattened membrane bag stacked on top of each other. They modify proteins and package them in vesicles for secretion from the cell. Vesicles are pinched off from the edges of membranes.
at the edges of glory body membrane are small bubbles of liquids that contain proteins. bubbles surrounded by membrane and called vesicles
lysosomes
small spheres that contain digestive enzymes able to break down large molecules. They break down proteins and other materials that are taken into the cell or breakdown worn out organelles. If it explodes, enzymes spread out and cell dies. materials taken into cell in vesicles, lysosomes join with vesicle and and enzymes break down materials in it.
formed from the Golgi body
mitochondria
spiracle elongated structures spread through cytoplasm. Have a double membrane and its own DNA. Folded membrane inside a membrane. larger SA
release energy for the cell through the process of respiration. Powerhouse of the cell, provide energy in the form of ATP
centrioles
near the nucleus. Pair of cylindrical structures perpendicular to each other.
involved in the reproduction of the cell they form spindle fibres
cilia/flagella
on the surface of the cell. Tiny hairs called cilia, if it is longer and fewer it is called flagella
they move mucus and trapped particles (cilia in windpipe)
flagella in sperm cell helps it swim
cytoskeleton
free in cytoplasm along the cell membrane
they are a framework of protein fibres that give the cell its shape and assists in cell movement. Made of microtubules and microfilaments
microtubule: keep organelles in place and/or move them around the cell.
microfilaments: moves materials in cytoplasm and the whole cell
act as railway tracks guiding organelle or molecules to particular places. not permanent structure as it can built up and broken down as needed by the cell.
why are cells small
there is a limit to how big a cell can be.
A small cell will have a larger surface area to volume ratio then a large cell.
cells have to be microscopic to function effectively.
A large cell could not support itself because it would not have enough surface to absorb the nutrients required, and remove the wastes produced by its large volume
homeostasis
The maintenance of a constant internal environment of cells despite fluctuations in external environment
body systems work together to ensure a constant body temperature, correct level of molecules or ions maintained, fluid levels and body are correct
functions of cell membrane
- it is a physical barrier: protect ourselves and separate cells cytoplasm from the extra cellular fluid. this is important because the composition of the cytoplasm and the extracellular fluid are very different
- regulates passage of materials: what enters and leaves, controls the movement of materials into and out of the cell. Achieves this through its semipermeable membrane
- sensitivity: protein receptors in membrane are sensitive to certain or particular molecules around it for example hormones. The cell membrane is the first part of the sale affected by any changes in the extracellular fluid
- support: inside part of membrane has microfilament’s attached, which is part of the cytoskeleton. there are also connections between the membranes of adjacent cells that give support to the whole tissue of which the cells are apart
cell membrane structure
membrane is the phospholipid bilayer (2 layers), The main building blocks are phospholipids.
1. hydrophilic head made of an alcohol and glycerol group
2. hydrophobic tail made of chains of fatty acids
3. glycerol backbone
phospholipids can move sideways and allow water and other nonpolar molecules to pass through into or out of the cell
proteins and other molecules are in bedded in the membrane, it is called the fluid mosaic model.
fluid= proteins/molecules are constantly changing positions
mosaic=composed of many different types of molecules
A variety of proteins and cholesterol molecules are embedded in the bilayer some past through the membrane others are only on the surface. Cholesterol makes the membrane more fluid.
membrane proteins
- channel proteins: form a central pole, allow small ions, water, and other small molecules to pass through by simple diffusion
- receptor proteins: receive information to provide a response (hormone, insulin)
- Carrier protein: are specific, allow certain materials to bind to it, For example only glucose, amino acids. allows facilitated diffusion for example glucose and active transport (specific membrane pumps)
- cell identity markers: identifies the sale as self to prevent attack by the bodies immune system. They have carbohydrate parts attached to it to help cells in recognising each other and certain molecules
membrane transport methods
- diffusion and osmosis
- Carrier mediated transport: facilitated diffusion (passive), active transport (active)
- vesicular transport: endo/exocytosis
diffusion
occurs in gases and liquids
movement of molecules from areas of High concentration to low concentration, until evenly distributed. Because cell membrane is fatty, so most water soluble substances cannot diffuse through it except for oxygen and carbon dioxide
factors:
1. Concentration gradient: concentration and distance
2. surface area: larger surface area creates a larger rate of diffusion
3. barriers: thicker barriers slow diffusion rates, pores in a barrier in enhance diffusion
4. temperature: higher temperature leads to higher diffusion rates because particles have more energy
bring in water, oxygen, carbon dioxide, alcohol, fatty acids, ions, lipids, soluble drugs
fat soluble substances diffuse through lipid part of membrane
molecules within cells move with diffusion
concentration gradient
when the concentration of a substance is different at two places: the substance will diffuse along the concentration gradient until the concentration of the two areas become equal
x axis= distance
y axis= concentration
greater the difference in concentration, the steeper the gradient and the faster diffusion occurs
osmosis
diffusion of water across a semipermeable membrane. What are molecules move from high concentration to low concentration
solute=sugar(other),solvent=water
The higher the concentration of the solute increases the osmotic pressure.
water diffuses from the more watery to the less watery side of the membrane
osmotic pressure: The pressure due to differences in concentration on either side of a semipermeable membrane
carrier mediated
facilitated diffusion
diffusion with help, where molecules diffuse across cell membrane with assistance of carrier proteins. carrier protein changes shape and molecule is released on the other side of membrane
diffusion takes place from high concentration to low concentration does not require ATP for example amino acids or glucose
carrier proteins: specific, can become saturated, and can be regulated by hormones for example insulin
proteins bind to molecules
bring in glucose and AA
carrier mediated
active transport
process of using ATP to pump molecules across membrane against the concentration gradient
they move from low concentration to high concentration
using active transport a cell can take in or pass out substances regardless of their concentration which is why energy is needed. For example membrane pumps sodium ions and potassium ions which are high in the nerve cells of the body
bring in glucose, certain ions, AA
endocytosis
process that brings materials into the cell
involves the cell absorbing large particles such as proteins or even whole organisms such as bacteria, viruses, from outside by engulfing them with the cell membrane to form a vesicle like a bubble with in the cytosol
brings in cholesterol, iron ions
The cell membrane folds around a particle until the particle is completely enclosed, the vesicles so formed then pinches off and suspended in the cells cytoplasm
exocytosis
release of molecules from the cell, things leaving the cell
contents of vesicle are emptied, vesicle formed inside cell then, membrane of vesicle fuses with the cell membrane and contents emptied into extracelluar fluid
empty secretions such as mucus or digestive juices
carrier proteins
specific: they will only buy to a particular molecule. for example the carrier that transports glucose can not transport any other molecules
saturated: once all the available carriers are occupied, any increase in the concentration of molecules to be transported cannot increase the rate of movement.
Regulated by hormones: they are important in coordinating the activities of carrier proteins
fertilised cell repeatedly divides and differentiates
what is differentiation?
process of specialisation of embryonic cells for particular functions (blood, bone, gland, nerve)
structural levels of human body
cell - tissue - organ - system - organism
tissue
group of cell with similar structure and function epithelial connective muscular nervous
organ
eg stomach
made of different types of tissues working together
stomach has all 4 tissues:
e: lines stomach to protect
m: churns food
n: transmits n impulses to coordinate muscle contractions
c: holds all tissues together
epithelial tissue
covering and lining tissue that protects
lines inside of organs
consist of cells very closely joined together
cells that vary in size in different tissues (thin&flat, column/cube shaped)
mouth lining, outside lung, outer layer of skin
connective tissue
supporting tissue that holds body parts together
made of widely spaced cells separated by noncellular material called matrix
eg: blood, bone, adipose (fat) tissue, ligaments (bone to bone), tendon (muscle to bone), cartilage
under skin there is loose connective tissue
matrix of blood is plasma
muscle tissue
contracting tissue that responds to stimulus
made of long, thin, muscle cells/fibres
responds to stimulus by contacting and relaxing
3 types of muscle tissue
skeletal: (striated/voluntary) attached to bones
arms and legs
smooth: (non striated/involuntary) in walls of many organ
uterus, stomach, blood vessels
cardiac: branched and striated with intercalated discs/involuntary) contacts to pump blood around body
involuntary: something you can’t control
nervous tissue
carries message in form of electrical impulses around body
found in brain, spinal cord, nerves
composed of neurons (nerve cells) with long projections from the cell body
stimulation of a neuron causes messages of to be passed along projections throughout the body
metabolism
total of all chemical reactions/processes occurring in your body
2 types
maintains a balance between energy released and energy used
catabolism
breaking down
large molecules broken down to smaller ones
energy released
cellular respiration
anabolism/synthesis
building up
small molecules built up to larger ones
energy required
amino acids to proteins
glucose to glycogen
lactic acid and oxygen to glucose
fatty acid and glycerol to lipids
enzymes
organic substance (protein) that speeds up chemical reactions without being altered or destroyed in the process organic catalyst (has carbon=organic) without them, chemical reactions would be too slow to sustain life
cellular respiration
glucose+oxygen—>ATP+co2+h2o
occurs in every cell to supply energy
1st stage is anaerobic in cytoplasm
2nd stage is aerobic in mitochondria
stage 1: glycolysis
breaks down one glucose molecule to make 2 two molecules of pyruvate (pyruc=vic acid C3H4O3)
also makes 2 molecules of ATP
occurs in cytoplasm of cell, doesn’t require oxygen
If no oxygen is present, pyruciv acid goes to lactic acid
lactic acid goes to liver nd recombines with oxygen to make glucose
stage 2: Krebs cycle and electron transfer system
Krebs cycle= citric acid cycle
series of reactions where pyruvate is completely broken down to CO2.
Krebs cycle make 2 ATP, electron transfer makes 34 ATP
in mitochondria, requires oxygen
ATP
adenosine triphosphate
made by joining an inorganic phosphate group to ADP (adenosine diphosphate)
phosphate group is joined with a very high energy bond that is easily broken
ATP stored energy in that bond, when the phosphate is removed, energy is released and ATP becomes ADP
energy used by the cell
60%: for heat to maintain temp
40%: forms ATP, used in body for muscle contraction, active transport, synthesis for growth and repair, transmission of nerve impulses, cell division, movement of things in and out of cell.
lactic acid
during high intensity exercise, O2 can’t be supplied fast enough, so muscles burn glucose anaerobically, producing lactic acid
lactic acid build up in muscle is toxic and causes fatigue and pain
lactic acid is taken by the blood to the liver where it is recombined to form glucose then glycogen (storage form of glucose)
oxygen debt
after exercise breathing is heavy so oxygen can be repaid
recovery oxygen: oxygen required after exercise
protein synthesis
process where small amino acids are linked together to make proteins
nutrients x6
substance in our food that is used to growth, repair a nd maintenance of body
organic has carbon. inorganic are transported in blood as ions
carbohydrates
main source of sugar for cells (sugar and starches)
C, H, O always 2x H than O
proteins
broken to amino acids. enzymes are made of proteins and important in metabolism C,H,O,N (S, P) 2 AA: dipeptide 10+ AA:polypeptide 100+ AA: proteins
lipids
fats
C,H,O much less O than carbohydrates
one glycerol molecule and 1/2/3 fatty acid molecules
triglyceride: glycerol + 3 fatty acids
glycerol can enter glycolysis pathway and is broken down to release energy similar to glucose
vitamins
act as coenzymes for many chemical reactions of metabolism
minerals
ions
na, k, ca, cl, i
co factors for enzymes
water
important in metabolism
dissolves substances
activation energy
energy required to start a chemical reaction
usually takes long time for reaction to gain this energy
but enzymes decrease activation energy needed so reactions occur faster
means cells can burn glucose at body temp instead of normally high temp of combustion
substrate
active site
products
substance that acts with an enzyme, locks in with active site if it fits
position where locking occurs,
chemicals resulting from the enzyme reaction
characteristics of enzymes x9
- are proteins, organism synthesises its own enzymes
- specific: catalyses one specific reaction type, no effect on other enzymes eg pepsin only break down protein
- small amount of enzyme catalyses a large amount of substrate
- an enzyme is not used up in the reaction it controls. however it can become inactive and more needs to be synthesised
- enzymes can be denatured (lose shape) by heat and lose catalytic properties
- optimum temp is 37ºC and pH varies. over 45ºC enzymes are denatured
- some only work if a second substrate called co-enzyme (organic) or co-factor (inorganic)are present
- work by lowering energy required to start reaction (activation energy)
- work on a lock and key principle
functions of blood
- transport nutrients and oxygen to cell
- transport co2 and wastes away from cell
- transport hormones to cells
- regulate pH
- thermoregulation
- protect against disease (WBC)🦠
- clotting to prevent blood loss
- maintain water and ion content in bodily fluids 💦
components of blood
liquid: palms 55%
non-liquid: formed elements 45% (cells and cell fragments)
erythrocytes
RBC
suited for o2 and co2 transport
have HGB (protein) and has no nucleus to make room for it ( when combine with o2, HGB is red)
large SA to V to speed up gas exchange
made in bone marrow, destroyed in liver/spleen by macrophages (120 days)😩
small, 8um and flexible to go through narrow capillaries
leucocytes
fight infections/provide immune responses
granulocytes: granular cytoplasm, lobed nucleus
agranular: lymphocytes and monocytes
macrophage is type of monocyte- phagocytic
few minutes to YEARS!!
get rid of dead or injured cells 😭(RIP) and invading microorganisms 🦠
thrombocytes
small cell fragments with no nucleus😔
1/3 of RBC🖕👌
made in bone marrow life span of a week
important in coagulation
plasma
91% water
rest is dissolved substances
glucose, AA, ions, wastes (urea: waste of protein metabolism), gases
oxygen transport x2
3% dissolved in plasma
97% carried in HGB to make oxyhemoglobin
this bond is v loose to breaks down easily to release oxygen
when o2 conc is high (capillaries in lungs), o2 combines with HGB easily
when o2 conc is low (cells) oxyhemoglobin breaks down
co2 transport x3
8% dissolved in blood plasma
22% combines with HGB to form carbaminohaemoglobin
70% carried in plasma as bicarbonate ions (HCO3-) (H+)
co2 diffuse into plasma because of con grad, most of it reacts with water to from carbonic acid. this then dissociates into hydrogen ions and bicarbonate ions
in lungs:
8% diffuses out
22% breakdown then diffuse
70% ions recombine to carbonic acid then breaks down by enzymes to water and co2, then diffusion
arteries
carry blood away from the heart
carry oxygenated blood
have thick, smooth, muscular walls with elastic fibres
no valves
high pressure blood because it is closer the heart, increase as ventricles contact
further down in skin because it contains high pressure blood
veins
carry blood toward the heart
carry deoxygenated blood
thin, relatively inelastic (pressure is constant) walls with little muscle
have valves
blood is under low pressure because most of the pressure is lost as it flows through the tiny capillaries
capillaries
Microscopic
connects veins and arteries
network
1 cell thick: thin for easy diffusion of nutrients and wastes
arteries
vaso
smooth muscle and elastic fibres (stretch and recoil)
Vasoconstriction: contraction to reduce the lume (inside space) size/diameter of artery to reduce blood flow to an area. reduce loss of body heat in cold temperatures, arteries constrict to let less blood go to the skin and more in the core region.
vasodilation: relaxing to increase lumen size, increase blood flow to an organ.In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation . This allows more heat to be lost from the blood.
adrenaline causes vasoconstriction in most arterioles, but vasodilation in skeletal/cardiac muscle
cardiac cycle
sequence of events that occur in one heart beat
systole and diastole
systole: when heart muscles contract, pumping
diastole: when heart muscles relax, filling
artrial systole/ventricular diastole: atria contracts forcing blood into ventricles
ventricular systole/ atrial dyastole: atria relax and refill while ventricles contact which forces blood into arteries
cardiac output
=stroke volume x heart beat
stoke volume= volume of blood forced from a ventricle each contraction
cardiac output= amount of blood leaving leaving a ventricle every minute
sinoatrial node
collection of nerve cells in the wall of the right atrium
pacemaker
starts each cardiac cycle by sending nervous impulses which cause the atria walls to contracts, nerve impulses reach the atrioventricular node causing ventricles to contract-> frequency of this is called heart rate
vasodilation and exercise
when you exercise, large increase in blood flow Is needed to supply oxygen and nutrients and remove carbon dioxide and heat
vasodilation of blood vessels in muscles and contraction to blood vessels
started by anticipatory response from nervous system
continued because wastes (CO2, lactic acid, heat) all act as vasodilators
antigen
protein molecules of the surface of erythrocytes that determine blood type
capable of stimulating formation of antibodies
antibodies
molecules in plasm that remove foreign bodies (pathogens)
leucocytes then engulf and destroy inactivated pathogens
specific to each pathogen
Rhesus factor
a further antigen on erythrocyte surface
rh- doesn’t have antigen and makes antibodies that destroy the Rhesus factor
rh+ person has the antigen that makes no antibodies that destroy the Rhesus factor
antibody for rh is not normally present in plasma only produced after exposure to it. 1st exposure sensitises person, so nay subsequent exposure leads to rapid production of antibodies
if wrong blood type is given
antibodies in plasma combine with antigens on the surface of foreign blood Agglutination occurs (clumping of cells)
types of blood transfusion x7
whole blood: blood taken with anti-clotting agent added (eliminates disease risk)
Autologous: patienst own blood used that was collected before surgery
red cell concentrate: blood centrifuged and only erythrocytes taken (anaemic/heart disease)
plamsa: used to provide extra clotting factors in severe bleeding and liver disease
platelets: when platelets are too low
Cryoprecipitate: plasma frozen and slowly thawed. contains many clotting factors and used for haemophiliacs
Immunoglobulins: group of proteins acting as antibodies extracted from blood of people that are immune to a particular disease.
blood clotting and defence
- injury to lining of a blood vessels exposes a rough surface to which plackets stick to
- sticking platelet attract others, so a plug is built at the site of the injury
- platelets release vasoconstricttors that enhance constriction of damaged vessels
^for small injuries - blood clotting factors form a fibrin cloth reinforces the seal. fibrin cloth form a mesh that traps blood cells
after clot is formed, clot retraction occurs(threads contract, pulling damaged blood vessel edges together,) as this occurs a fluid called serum is squeezed out. then scab formed–>acts as a mechanical barrier to the entry of pathogens.
blood coagulates to prevent blood loss from injured tissue.
clotting factors catalyse the conversion of plasma protein to an active enzyme
the nose structure and function
nasal cavity with l&r chamber (nostrils) that lead to pharynx
projections known as conchae increase surface area
filters (hair), warms (capillaries), moistens (mucus) the air before it enters the lungs
has olfactory receptors
enhances sound produced in speech
mucus and hair trap dust
pharynx
air from nasal cavity passes through here
13cm, direct air to larynx
used to pass food to oesophagus
larynx
stretched between cartilage are two folds of mucus membrane called vocal folds
the edges have elastic ligaments that vibrate (vocal chords)
trachea
has c-shaped cartilage bands that allowing the oesophagus to expand into the gaps in the trachea when swallowing
lined with ciliated mucus membrane to trap solid particles
mucus is produced from goblet cells
bronchi
where trachea divides into secondary and tertiary bronchi
kept open with cartilage and lined with cilia and mucus
bronchioles
very fine tube that lead to the alveoli
walls of smooth muscle, no cartilage
alveoli
around 300 million each lung
tiny air sacs, in clusters, wall have very thin membrane for diffusion
1 cell thick, large sa
surrounded by dense network of capillaries
chemical surfactant coast the inside alveoli to lubricate it and prevent friction and closing of alveoli
lung structure
right has 3 lobe
left has 2 lobe
covered in pleural membrane, moist to reduce friction as lungs move in chest
between the membrane is a pleural cavity filled with pleural fluid, allows pleura to slide over each other whilst breathing
intercostal muscles
muscles between ribs, internal and external
when the external muscles contract they they pull the ribs upwards and outwards, increasing volume of thoracic cavity
contraction of the internal muscles pulls ribs closer, decreasing the thoracic cavity. this increase pressure inside lungs and air is diffused out
diaphragm
dome shaped muscle
contraction increases volume of thoracic cavity
how lungs are specialised for gas exchange
x5
- alveoli give lungs a very large internal surface area, so lots of gas can be exchanged in a short amount of time
- each alveoli is well supplied with blood vessels, so that as much blood as possible is close to the air in the alveolus. the continuous flow of blood helps maintain a difference in concentration of o2 and co2 in blood and lungs. concentration gradient is necessary for diffusion
- wall of alveolus is very thin (1 cell thick), gas doesn’t have to travel far when moving in and out of blood.
- lungs positioned deep inside body to prevent excessive evaporation of fluid that covers the respiratory surfaces, it is important that the alveolus membrane is covered by a thin layer of moisture because gases can only diffuse in and out of the blood when they are dissolved in fluid.
- the lung volume can be changed by movements of the respiratory muscles, so that the air is made to move in and out of lungs. constant changing of air in the alveoli helps to ensure that there s always a difference in o2 and co2 concentration in the lungs and blood.
inspiration
external intercostal muscles contract (ribcage up + out)
diaphragm contracts chest cavity extends down
increase in lung volume
air flows from H-L (H=outside body, L= inside lungs)
breathe in
Expiration
intercostal external muscles relax (ribcage down + inward) (passive breathing)
diaphragm relaxes, chest cavity pushes up
lung volume decreases, more pressure
air flows from H-L (H= inside lungs, L= outside body)
breathe out
which muscles contract during forced breathing
internal intercostal muscles
gas exchange in alveolus
blood in capillaries is from the pulmonary arteries.
this blood has low level of oxygen, lower than the concentration of oxygen in the alveolus. oxygen dissolves in the moisture on the inside of the alveoli and diffuses through the membrane through capillary walls and into blood.
the blood arriving at alveoli has high concentration of co2. (waste from cells) so the concentration of co2 in capillaries is higher than the concentration in the alveolus. co2 diffuse out of blood and into the alveolus. this is why the expired air has more co2
how is concentration gradient for O2 and CO2 maintained?
constant flow of blood through capillaries.the new blood pumped is low in o2 and high in co2 so conc grad is maintained
constant movement of air in and out of lungs. the air is high in o2 and low in co2
the mouth
mechanical:
jaw and teeth cut, tear, crush and grind food
tongue mixes it up with mucus into a round lump called bolus
chemical:
salivary amylase ptyalin begins starch breakdown
salivary glands
3 types, 2 of each
- parotid salivary gained (front of ear)
- sublingual salivary gland (under the tongue)
- sub mandibular salivary gland (under mandible bone)
upper jaw=
lower jaw=
maxilla
mandible
types of teeth and function
incisors: (4) biting and cutting, chisel shaped
canines: (2) tearing, pointy edge
premolars: (4) crushing and grinding
molars: (6) crushing and grinding
32 together
tongue to stomach
food is swallowed
bolus is pushed into pharynx by tongue
oesophagus: made of mucosa, muscle (circular and longitudinal)
oesophagus pushes food from the mouth to the stomach by a wave of circular, muscular contractions called PERISTALSIS. movement lubricated by mucosa, prevents friction
stomach
after passing the diaphragm, the oesophagus reaches the stomach
mechanical:
waves of muscular contraction churns food and mixes it with gastric juices (HCl and enzymes) into thick soupy liquid called chyme
stomach has third muscle (oblique) to assist with churning
chemical:
gastric juices made in gastric glands of mucosa, contains enzyme pepsin (gastric protease) that begins protein breakdown. pepsin works in acidic conditions, that’s why it need activated by Hal to go from pepsinogen to pepsin
absorption: only alcohol and drugs absorbed in to blood
stomach wall lining
deep folds called rugae line stomach to help it expand to increase volume
first is the cardiac sphincter then it is the pyloric sphincter
thick mucus walls
stomach to small intestine
chyme goes into the duodenum (1st part of small intestine), through the pyloric sphincter (prevents food spilling into the duodenum too soon)
transferred by peristalsis (2-8hrs)
parts of small intestine
- duodenum
- jejunum
- ileum
duodenum and jejunum
mechanical:
waves of muscular contractions (L&C walls of small intestine),churn the food, peristalsis
bile stored in gall bladder, and made in liver, is secreted through duct and emulsifies fats
chemical:
pancreatic juices from the pancreas enter the duodenum (pH8) and neutralises the chyme, contains enzymes
- pancreatic protease: proteins to amino acids
-pancreatic amylase: carbohydrates to simple sugars
-pancreatic lipase: fats to fatty acids and glycerol
intestinal juice fro intestinal glands in the mucosa completely chemical digestion
bile
emulsifies fats (breaks them down to tiny droplets, doest chemically change it)
has salts in it, not an enzyme
travels via duct to duodenum, helps neutralise chyme
increases surface area of fats so pancreatic lipase cancan quicker
ileum
absorption
most products of digestion (V+M, H2O) are absorbed into the blood capillaries of the villi through diffusion, osmosi and active transport (depends on conc)
fast and fat soluble vitamins absorbed into the lacteals of the lymphatic system and transported to the chest, where they enter the blood and go to the liver
lacteals are permeable to larger fat molecules
villi and microvilli in small intesine increase surface area to increase absorption rate
large SA of small intestine
very long (6m)
inner mucosa lining has many folds
mucosa has villi on it, cells covering villi have further projections (microvilli)
has dense network of capillaries to absorb nutrients
epithelium is very thin (1 cell thick)
ileum to large intestine
waste products of digestion go through large intestine
1.5 m long, no villi but mucosa is secreted to lubricate
bacteria breakdown remaining organic compounds
vitamins, minerals and water absorbed into blood, leaving contents semi-solid
faeces stored in rectum and eliminated through anus
faeces consists of, undigested cellulose, bacteria, bile, pigments, cells.
FUN FACT: cellulose stimulates movements of the alimentary canal.
large intestine structure
caecum (appendix is attached) appendix (lymphatic tissue) ascending colon, transverse colon, descending colon sigmoid colon rectum anus
what do gastric glands secrete
up to down
mucus
pepsinogen
Hal
villi and absorption
fatty acids + glycerol: diffusion into lacteal
AA: active transport
water and water soluble vitamins: diffusion
simple sugars: active transport
function of lymphatic system
fluid balance
fat absorption
immunological defence
returns tissue fluid back to circulatory system
major organs of lymphatic system
spleen
thymus gland
Lymphatic vessels
lymph nodes
lymph and fluid balance
at the atrial end of the blood capillary, fluid tends to leak because of high pressure, some fluid returns at the venous end of capillary, the rest of the fluid now in tissues is returned as lymph.
clear watery liquid formed from interstitial fluid (between cells). help destroy dangerous bacteria
90% of this fluid goes back into the blood capillaries and the rest enters the lymphatic vessel (interstitial fluid in a lymphatic vessel is called lymph)
the lymph capillaries lined with overlapping epithelial cells that allow fluid to enter. Capillaries open to large vessels, often with valves to prevent back flow
lymph nodes
occur at intervals along lymphatic vessels
where lymph vessels carry lymph to
surrounded by capsule of connective tissue
large particles are trapped in meshwork of fibres as lymph flows through spaces in lymph node
lymphocytes and macrophages (phagocytosis) are produced to fight off invaders in lymph.
what happens when large quantities of microorganism overwhelm the lymph nodes
formation of lymphocytes increase and nodes get swollen
what happens to lymph after lymph node
sent through the efferent vessel and sent through the right lymphatic or thoracic duct where merges with the veins and the fluid reenters the circulatory system
lymphocytes
small WBC that work on bacterial and viral infections
macrophage
phagocytic cell that destroys pathogens
neutrophil
move around and seek pathogens
function of excretory system
maintain right levels of h20 and dissolved substances in our body (osmoregulation)
pass out metabolic wastes from body to exterior
organs of excretory system
lungs: release co2 and h20 vapour from cellular respiration
liver: convert substances in form we can excrete
skin: sweat glands, removes waste, and sweat for cooling, salt. contains byproducts
alimentary canal: passes out bile pigments from breakdown of haemoglobin to faeces
kidney: principal excretory organ, filters blood stream to remove toxic waste products
skin
main function is protection and temperature regulation and excretion of wastes
epidermis (closely packed epithelial cells/tissues)
dermis (connective tissue) has sweat glands, hair follicles, nerves and capillaries
subcutaneous layer (innermost skin layer)
sweat glands excrete 500ml of water a day contains salts, urea, lactic acid, drugs
sweat glands are found in lower layers of skin, a duct carries sweat to a hair follicle or skin surface where it opens at a pore. cells surrounding glands contract and squeeze the sweat to the skin surface
liver
hepatic
upper right quadrant of abdomen
under diaphragm
4 lobes
main job is to process products of digestion, also filters blood and prepares materials for excretion
deamination
if other energy sources have been used up, body can metabolise large amounts of protein.
main byproduct of breaking down proteins is ammonia (NH3), excess protein in diet can’t be stored
deamination: removal of the amino group from excess amino acid molecules in the liver forming ammonia
AA + O2 —(enzymes)–> carbohydrate + ammomnia
amino acids are toxic so they are made into urea (less toxic molecule)
the carbohydrate is broken down into energy
energy + CO2 + NH3 —-> UREA + H2O
ammonia is converted to urea compound made by CO2 and NH3 in the liver.
urea circulates in blood and is filtered out by kidneys
urea is low toxicity so it needs water to dissolve it in and get rid of it (urine)
worn out cells are a source of protein and are broken down into AA
functions of the liver
x10
- deamination
- detoxification: alcohol, drugs, antibiotics
- hormone removal, deactivates and converts to a form to be excreted
- dead RBC and haemoglobin are broken down in liver and passed out with faeces
- carbohydrate metabolism: excess glucose turned to glycogen for storage and glycogen turned back to glucose when needed. depends on body needs
- lipid metabolism: excess carbs to fat
- heat production, main heat producing organ in body
- production of bile: emulsifies fat in duodenum
- stores vitamins and minerals
- protein synthesis
fluid contents in kidneys
water most abundant in body 40-80%
intracellular and extracellular fluid
water intake=water outputs
amount of water consumed and urine formed is regulated by brain receptors and ADH hormone (antidiuretic hormone) which target nephrons and stops them from releasing water through urine
ADH produced when body is dehydrated
regions of the kidney
renal cortex:outer position, dark red, contains bowman’s capsule
renal medulla: innermost region, holds renal pyramids (8-18), loop of henle, pale pink
renal pelvis: inner layer, cream colour, collects urine from collecting ducts -> 3 major calyces-> renal pelvis before it goes to bladder. acts as funnel for urine flow into ureter
nephron
microscopic
functional unit of kidney
nephron = glomerular capsule + renal tubule (5cm long) + associated blood supply
I million nephrons each kidney
sections of nephron
x5
- renal corpuscle (glomerular capsule)
- proximal convoluted tubule.
descending limb of loop of henle - loop of henle
ascending limb of loop of henle - distal convoluted tubule,
- collecting ducts
renal corpuscle
consists of glomerulus (knot of capillaries) inside glomerular capsule (double walled cup that that surrounds glomerulus)
afferent: enters, arteriole going into RC
efferent: away, arteriole leaves glomerulus
filtration takes place in real corpuscle
blood flow in nephron
- renal artery (blood from aorta) divides into afferent
- afferent arteriole forms knot of capillaries (high bp)
- efferent arteriole breaks up into network of capillaries called peritubular capillaries
- peritubular capillaries surround PCT, desc and asc limb of LOH and CD
- venule
- renal vein to inferior vena cava
things get squirted out from glomerulus to glomerular capsule
steps of urine formation
glomerular filtration
selective reabsorption
tubular secretion
glomerular filtration
high BP in GC is due to the afferent arteriole having a wider diameter
efferent arteriole leaving glomerulus is narrower, resistance to blood flow
High BP forces small ions, glucose, AA, H2O, through capillary walls and into bowman capsule space
large molecules, (RBC, large proteins), remain in capillaries
the filtrate is collected by Bowmans capsule and enters tubule
selective reabsorption
of filtrate by cells that line renal tubule (H20, salts, glucose, AA, vitamins, minerals, ions)
water leaves membrane on descending part of LOH
Na and Cl reabsorbed on ascending limb of LOH (so doesn’t lose more water)
under hormonal control of ADH where more or less water can be reabsorbed
facultative reabsorption: active reabsorption of H20, ATP is needed
ADH causes kidneys to retain water (alcohol interferes with this action
tubular secretion
adding materials/molecules to filtrate
active transport
peritubular secretion into tubes of nephron, last chance for unwanted materials to leave the body
remove H ion to regulate pH
removes ammonium ions as well
water and other substances not reabsorbed drain forms the collecting ducts into renal pelvis to ureter and bladder
ADH in kidneys (CD), to remove water from urine, decrease urine output, makes urine more concentrated
dark yellow instead of pale yellow
structure and function of nephron
x4
- glomerular capsule surround glomerulus to collect fluid filtered out of blood capillaries
- arteriole leading out of glomerulus is narrower, so this raises BP so more fluid is filtered out of blood
- tubule has 2 sets of convolutions and a long loop so that each tubule has a large SA for secretion and reabsorption
- 1 million nephrons each kidney, increase surface area for reabsorption
urine composition
0.5 litres per day lost to remove wastes
more water leads to increase urine output and decrease in concentration
99% of water reabsorbed
no protein
no glucose
contains uric acid (breakdown of nucleic acids)
and creatinine (breakdown of creatine phosphate)
96% water
2% urea
1.5% various ions
0.5% other (creatinine, uric acid)
tranport in glomerular filtration
passive: water urea glucose AA vitamins salts
transport in selective reabsorption
passive:
water
active: salts glucose AA vitamins Na, Cl ions
transport in tubular secretion
active: H ion NH4 ion creatinine toxins drugs (penicillin) neurotransmitters UREA water (under ADH influence)
function of musculoskeletal system
movement
postural support
heat production during cold stress (shivering)
properties of muscle unique to other cells
x4
- contractibility: cable of getting shorter, contracts and relaxes
- extensibility: can be stretched
- elasticity: when stress is removed, they return to original shape/length (recoil)
- excitability: nerve stimulations, muscles are activated by nerve impulses from the brain
microstructure of muscle cell
muscle cell is an elongated cyclinder that lie parallel to each other, many nuclei and mitochondria and has sarcolemma and sarcoplasm.
made of bundles of muscle fibre held together by connective tissue.
connective tissue have hundreds of myofibrils which is made of myofilaments which is made of actin and myosin
sarcolemma
sarcoplasm
sarcoplasmic reticulum
cell membrane around muscle cell
cytoplasm of muscle cell
t tubule, contains, stores, recreates Ca ion
sarcomere
small unit of skeletal muscle that contracts
made of acting and myosin filaments
sections/division of sarcomere:
- Z lines, boundary of sarcomere. where 1 joins onto the next, anchors for actin
- A band: thick filament region (dark band is myosin)
- I band: point between thick filaments, so thin filaments (light band are actin)
- H zone: distance between thin filaments in middle
- M line: midline of sarcomere
myosin structure
head, neck, tail
head: ATP binding sited actin binding site
myosin heads stick out of filaments and act as cross bridges.
moving myosin heads creates a power stroke resulting in muscle contraction
movement is driven by ATP
filaments do not move
actin structure
2 proteins chains wrapped around each other makeup actin
proteins are:
- troponin: small round proteins that allow Ca ion to it. Ca ion binding site
- tropomyosin: long thin strand, blocks the myosin binding site, acts as regulator
actin filament and actin binding proteins regulate accessibility of the myosin heads.
actin moves, not myosin
sliding filament method
x9
- nerve impulses stimulate muscle fibres
- ATP breakdown into ADP and phosphate group, which provides energy. binds to myosin head at binding site
- calcium binds to troponin at binding site and moves tropomyosin out of its connection
- myosin heads attach to actin
- cross bridges form
- myosin pulls actin filaments towards centre of sarcomere, movement occurs
- actin sliding across myosin
- sliding of filaments occurs due to continuous attaching and detaching of myosin heads on actin filaments (breaking and remaking cross bridges-like rowing)
- results in muscles shortening, contraction
filaments don’t change in size
structure of muscle during contraction
I band shortens h band shortens Z lines come closer together (shorten) sarcomere shorten by about 1/3 of its resting length a band remains the same length
muscle tone
skeletal muscles are never completely relaxed, in mild state of tetanus
many different fires take it in turn to contract but without movement
muscle tone is important when standing/sitting: stabilises skeleton and constantly adjusts to maintain posture and balance
eg head is her up by partial contraction of neck muscles
maintenance of muscle tone when active or at rest is complex
receptor cells in muscles initiate sin voluntary nerve responses in spinal cord and brain to adjust muscle tone
skeletal muscles working together
biceps and triceps
agonist, prime mover: contracting muscle (bicep), causes desired action
antagonist: relaxing muscle (tricep), have opposite reaction
origin:end of muscle fixed to stationary bone
insertion: attachment of the other end of muscle to movable bone
origin of bicep: shoulder, scapula
insertion of bicep: forearm, attached to radius
origin of tricep: shoulder, scapula and humerus
insertion of tricep: forearm, ulna
synergists: helps an agonist or prime mover
fixators: when synergist immobilises a joint, keeps joint firm and still during movement
blood flow in nephron
renal artery to afferent arteriole to renal corpuscle
to efferent arteriole to peritubular capillaries
peritubular capillaries surround the proximal and distal convoluted tubules, limbs of LOH, CD
venous blood drains from the network of capillaries and leave kidney in renal vein
structure of muscle cells
held together in bundles, sheath of connective tissue surrounds each bundle so it can function as an individual unit
connective tissue allows adjacent bundles to slide easily over each other as they contract
sheath of connective tissue join each other and towards the end of the muscle they taper and blend
CT gives muscle toughness
factors influencing enzyme activity
x7
- high conc of enzyme increases rate of reaction
- increasing substrate increases rate of reactions rate.
increase chances of contact with enzymes. has limits because enzymes can be occupied - products need to be readily removed or it will decrease reaction rate
- temp
- pH
- many need co factors to change shape of active sit so enzymes can combine with substrate
- enzyme inhibitors slow/stop enzyme activity. controls reactions eg penicillin and bacteria enzyme that involves in cell wall construction
emphysema
long term exposure to toxins
cause damage to alveoli making them lose their elasticity reducing internal surface area
loss of elasticity means that lungs are always inflated and breathing requires voluntary effort
lung cancer
development of tumour in lungs
common in bronchi walls, irritates mucous membrane causing excess mucous production which make alveoli rupture
lung infections
Pneumonia: bacterial, fungal, viral
tb: bacterial
inflammation from infection causes secretion of fluid and mucus into alveoli -> reducing amount of air they have
asthma
allergic response to foreign substances that enter the body
muscles around bronchi go into spasm causing narrowing making it hard to breathe
less o2 to cells
constipation
when large intestine movements are reduced and contents remain their for long time. poo is harder
lack of cellulose
diarrhoea
frequent defection of watery faeces
irritation of both intestines, increase peristalsis so contents mover through before enough water is absorbed
fibre in diet
soluble fibre intake lowers cholesterol
they trap fats in intestines and prevent their absorption into the body
coeliac disease
unable to tolerate gluten
if they do, immune system attack villi in small intestine, meaning nutrients not absorbed as well which could lead to malnourishment
kidney stones
solid crystals built up in kidneys, when urine urine is too concentrated and insuffienct fluids
small crystals pass without too much pain
large crystals get stuck in thin tubes and cause lots of pain
kidney failure
when kidneys lose ability to excrete waste and control fluid levels
most affect glomeruli and decreases it ability to filter blood
I-> RBC and proteins may leave blood into filtrate
if too many proteins are lost there is decrease in blood protein and increase in fluid tissues leading to swelling
dialysis
method of waste removal when kidney failure occurs
peritoneal dialysis
peritoneum:membrane lining abdominal cavities and organs, has a rich blood supply
occurs inside body, using peritoneum as a membrane across which waste can be removed
catheter (tube) placed through wall of abdomen and 2/3 L of fluid (with blood products and no waste) is passed through tube and wastes in blood diffuse to tube
every day
haemodialysis
passing blood through dialysis machine
blood passes through lots of tubes made of semipermeable membrane and immersed in fluid (no waste) waste from blood diffuses into tubes
4-5 hours for 3 times per week
kidney transplant
transplantation of kidney into a patient with end stage kidney disease (kidneys lose 90% ability to functions properly) only one kidney needed
adv: better quality of life lower death risk fewer dietary restrictions lower treatment cost
disadvantage: risk of infection risk of blood clots and bleeding failure or rejection of donated kidney *after kidney is transplanted-> you need to take anti-rejections drugs or immunosuppressant drugs
