Tissue Structure And Function Flashcards
Epithelium, muscle, connective, nervous
What type of control is exhibited in smooth muscle?
Involuntary control
Where can smooth muscle be found?
In the walls of hollow organs such as the stomach and bladder.
What’s the proteins in muscle fibres called?
Actin and myosin
What’s a myelin sheath and what cells is it made from?
Schwann cells form the myelin sheath and this acts as an insulator to stop the electrical signal from leaving the cell too soon
What is the sarcomere?
Unit of contraction between muscle fibres
What are excitatory nerve impulses
Propagates (produces) impulses and stimulates brain
What are inhibitory nerve impulses?
Inhibits impulses and calms the brain
What is acetylcholine and roles?
Chief neurotransmitter
Controls muscles
Dilates blood vessels
Controls heart heart
What is homestasis?
Maintain internal environment despite external examples
What is thermoregulation?
Regulation of temp
What is osmoregulation?
Regulation of water
What temperature do enzymes work best at?
37 degrees Celsius
What is ADH?
Anti diuretic hormone
Where are the osmoreceptors?
In the hypothalamus
What gland produces ADH?
Pituitary gland
What does ADH do?
Causes the kidneys to absorb water, to keep water in the body
What does less ADH mean?
Less absorption of water so more urine produced
What are the main facts of capillaries?
One cell thick
Diffusion of oxygen and minerals to cells
Microscopic vessels
Take waste products away
What detects changes in blood temperature
The brain
What is sarcoplasmic reticulum responsible for?
Stores calcium ions which controls ATPase activity so this controls the contraction of muscles
What is the H zone
Myosin only
What is the Z line
Different sarcomere, line/space between them
What is the A band?
Both actin and myosin
Must overlap to contract
What is the M line?
Holds together the myosin filament and actin
What’s a heart’s pacemaker?
Sinus node continually generating electrical impulses (normal rhythm)
The specialised cells are at the top chamber (atrium) causing it to contract
What are the features of veins?
Large lumen Thin Elastic wall Carry deoxygenated blood back to heart Low blood pressure Has valves for blood flow
What are the features of arteries?
Small lumen
Thick elastic walls
Oxygenate blood
High blood pressure
What are the features of capillaries?
One cell thick
Microscopic vessels
Diffusion for gas exchange and minerals
Arterioles and venules
What are the types of Epithelial tissue
Squamous
Columnar ciliated
Endothelium
Features of squamous cells?
Where are they found?
Flat Surface of skin Lining if hollow organs Lining respiratory and digestive tracts Diffusion and filtration
Features of ciliated epithelium?
Where are they found?
Made of columnar ciliated
Cillia (Hair-like)
Mucus secreting goblets cells
Move particles out of the body
Features of endothelium cells?
Where are they found?
Line every blood vessels one cell thick
Heart chamber and lymphatic vessels which carry excess blood plasma around the body
Features of coboidal cells?
Where are they found?
Kidneys
Overies
Secretion and absorption
How do cardiac muscles tissues join together?
By intercalated disc
Features of fast twitch muscles
More powerful movement Shorter duration Fatigue Anaerobic Less blood supply (less capillaries) Less myoglobin which stores oxygen Less mitochondria so less ATP
More lactic acid produced causing muscles to fatigue
Features of slow twitch muscles
Fatigue resistant Smaller movements More mitochondria for ATP Red, more blood supply More myoglobin which stores oxygen
Less lactic acid produce so less fatigue
What is the process of phagocytoesis mean?
White blood cells engulf dead cells and bacteria
What things/organs make up respiratory system?
Nose Pharynx Larynx Trachea Bronchi Lungs
What is the respiratory system responsible for?
Inspiration
Expiration
What are the features of alveoli?
Lots of capillaries for gas exchange
Moist surface to allow gases to diffuse more easily
Large surface area
One cell thick
What is the threshold for action potential?
-55Mv
What is the resting for action potential?
-70Mv
What lifestyle factors cause atherosclerosis?
Lack of exercise
Smoking
Drinking
Diet with too much fat
Stress
How do pesticides kill small animals?
Acetylcholine builds up in cleft
Therefore constant depolarisation of post synaptic membrane
So muscles contract permanently
Where are ciliated columnar cells found in the body?
Trachea and bronchi
What are key features of ciliated columnar cells?
Lots of mitochondria
Cilia (tiny hairs)
Goblet cells produce mucus
What does COPD stand for
Chronic obstructive pulmonary disease
What does COPD cause?
It causes the cilia to slow down and stop beating and they eventually die
therefore mucus builds up and the airways become clogged up
Therefore you cough to move this mucus
But lots of coughing ruptures the thin epithelial cells in the alveoli
This means less gas exchange can take place
And a good place for pathogens to invade
What is the main cause of COPD?
Smoking
What is atherosclerosis?
Atherosclerosis Fatty deposits (atheroma) can block the artery or lead to a blood clot blocking it (thrombosis)
What major diseases can atherosclerosis cause?
Coronary disease
strokes
Angina (short periods of tight chest pain)
Heart attacks
Peripheral arterial disease (where blood supply in your legs is blocked)
Describe how atherosclerosis develops?
The endothelial tissue lining is damaged by smoking or high blood pressure
Low density of lipoproteins (LDL cholesterol) accumulates in the artery wall
This causes inflammation so white blood cells move into the area
This leads to a build up made of LDL cholesterol, the white blood cells, calcium salt and fibres Plaque formation (atheroma)
This can lead to an increase in blood pressure and this will damage the endothelial tissue even more
Describe how smoking can lead to atherosclerosis
The artery becomes narrow and less elastic
Blood flow is restricted
There is a bigger risk of blood clotting
Blood pressure rises and this causes the endothelial tissue to be damaged
What are the types of asexual reproduction?
Binary fission
Budding
Fragmentation
Parthenogenesis
What is reproduction?
The process by which an organism makes offspring
What is the fertilised egg with sperm called
Zygote
How many chromosomes does a egg have?
23 chromosomes
Where does binary fission occur?
In bacteria
Where does budding occur?
In yeast
Where does fragmentation occur?
Star fish
Where does Parthenogenesis occur?
In reptiles
How does Parthenogenesis occur?
It develops from one egg to embryo without fertilisation
How does fragmentation occur?
Parts break off and become an embryo
How does budding occur?
Parent cell has a growth and it falls off and becomes an embryo
How does binary fission occur?
Like mitosis but in bacteria
Copy genetic info and divides to become a new cell
What is a haploid?
Cell that contains 23 chromosomes
What is a diploid
Cell that contains 46 chromosomes
What is the flagellum for?
Motility
What is the acrosome and function?
Head of the sperm cell
Carries digestive enzymes that break the outer membrane of the egg cell
What does the plasma membrane do for the flagellum?
Same as normal plasma membrane controls what enters and leaves the cell
What is the mid piece for on a sperm cell?
Packed with lots of mitochondria to provide energy for the flagellum
What does LH mean?
Luteinizing hormone
What does FSH mean?
Follicular stimulating hormone
Where is LH and FSH produced
Pituitary gland
What are key features of egg cell?
Largest cell
Non-motive
Carries genetic information
Provides nutrition to embryo until it sinks into the uterus and placenta takes over
What is the zona pellicide?
Glyprotein layer
Barrier to extra sperm
What is the Corona radiata?
Follicular cell layer
Provides nourishment to the cell
What is the cortical granules?
Prevents polyspermy
More than one sperm fertising the egg
What is cytokinesis?
When cytoplasm divides
How many daughter cells do you get from meiosis
4 daughter cells
What is meiosis?
A cell divides twice to produce 4 cells containing half the original DNA
Which cells do meiosis?
Sperm and egg
What cells do mitosis?
All cells but egg and sperm
What is mitosis?
When a cell divides into 2 daughter cells that are genetically identical
What is dopamine?
A neurotransmitter
What happens in Parkinson’s disease and how is it caused?
Brain cells stop working properly and are lost over time
Decrease amount of dopamine leads to Parkinson’s disease
When do the symptoms of Parkinson’s disease appear?
Symptoms appear when the brain can’t make enough dopamine to control movement properly
What are the symptoms of Parkinson’s disease?
Abnormal brain activity
Tremor (shaking)
Slowness of movement
Muscle stiffness
What does L dopa do?
It crosses the blood brain barrier and is converted to dopamine
It increases the amount of dopamine stored or released by the presynaptic neuron, therefore normal levels of dopamine stimulate the postsynaptic neuron
What is carbidopa?
Medication that prevents levodopa (L dopa) from being broken down before it reaches the brain
What are the symptoms of atherosclerosis?
Chest pain
Pain in limbs where the artery might be blocked
Difficulty breathing
Fatigue
Confusion (if in brain)
Weak muscles
What increases your risk of atherosclerosis?
Increasing age
Smoking
Diet high in fats
Lack of exercise
Overweight
Alcohol
Family history
Other conditions, high blood pressure, high cholesterol and diabetes
What is the treatment to atherosclerosis?
Lifestyle changes
Medication- statin medications to control or lower cholesterol
Coronary angioplasty (stent placed in artery)
Coronary artery bypass grafting - arteries/veins from other areas of the body are used to bypass the affected artery
Carotid endarterectomy- remove plague from the carotid artery in the neck
What is Carotid endarterectomy?
Remove plague from the carotid artery in the neck
What is Coronary artery bypass grafting
Arteries/veins from other areas of the body are used to bypass the affected artery
What is Coronary angioplasty?
stent placed in artery
What are the risk factors of depression?
Being the victim of abuse/neglect
Experiencing difficult life events such as losing a job
Suffering from serious physical conditions such as cancer
Low self-esteem
What happens if you have different levels of serotonin?
High levels - happy
Low levels - depression
Imbalance of serotonin - OCD, anxiety, panic attacks, anger management issues
What is the treatment for depression?
Antidepressants medication - prevents serotonin from being reabsorbed by the body so levels are high
Mediate
Fresh air and sunlight
Exercise
What tissues make up blood vessels?
Endothelial tissue
Endothelium
What is the path nerve impulses take?
Receptors, sensory neurones, relay neurones (CNS), motor neurones, effectors
What does depolarisation mean?
When the action potential becomes less negative than the outside.
With a potential difference of -50mV (threshold)
What does polarised mean?
That the membrane is at resting potential -70mV
What does saltatory conduction mean?
Saltatory conduction is the process of signal jumping when the action potential reaches a note of Ranvier
So sodium ions diffuse into the axon membrane they displace potassium ions
Where does saltatory conduction occur?
Only happens in myelinated nerves
and it increases the speed of the action potential
What affects the speed of action potential.
Axon diameter - the larger the axon the faster the conduction
Myelination of neuron - the nerve impulses travel faster if the neuron is myelinated
The number of synapses involved - the fewer synapses there are to cross the fast at the communication
What is at the end of the presynaptic neuron?
The synaptic bulb
What are the features of non myelinated nerves?
Small diameter
no myelin sheath
slow impulses
no nodes of Ranvier
transmits aches soreness and temperature changes
What are features of myelinated nerves?
Large diameter
Have myelin sheath
fast impulses
Nodes of Ranvier
transmits sharp pains
What does
Dog
Run
Home
Mean?
Depolarisation
Repolarization
Hyperpolarization
What are channels function and how do they work?
They are voltage-gated which means they open and close at certain voltages to let ions in via diffusion
What are pumps function and how do they work?
Pumps grab irons and make the move
The pumps need active transport to return the ions where they were at the start
What happens in the first step of action potential?
A stimulus opens the sodium channels so Na+ ions diffuse into the cell and makes the voltage starts to rise above -70mV
What is the second step of action potential?
Depolarization
When the voltage reaches the threshold 50mV the voltage gated sodium channels open
This causes lots of Na+ ions to enter the cells so the voltage rises rapidly to 30mV
What is the third step of action potential?
Repolarisation
The sodium Na+ and potassium K+ gates open
This means the ions leave the cell and the voltage falls to -90mV
What is the fourth step of action potential?
Hyperpolarisation
The pumps grab the sodium and potassium ions
and return the resting potential to -70mV
What is statory conduction
The signal jumping from gap to gap in the nodes of Ranvier
The myelin sheath is an insulator which stops the Na+ ions entering the cell
so depolarization can’t occur there
What happens when a muscle contracts?
The thin actin filaments move between the thicker myosin sing filaments which makes the sarcomere shorter
Special proteins on the myosin filements drag the actin filaments inwards
What are myofibrils and their function?
Myofibrils are made up of sarcomeres
The function of myofibril is to perform muscle contraction
What is a electrocardiogram?
ECG is a test that checks the hearts activity by measuring the electrical activity of the heart
What is a electroencephalogram?
EEG is a test that measures the electrical activity of your brain
What are the symptoms of COPD
Breathlessness
A persistent chesty cough - smokers cough
Frequent chest infections
Persistent wheezing
What is emphysema?
Damage to the alveoli
What is chronic bronchitis?
Long term inflammation of the airways
What happens in emphysema?
What are some features of emphysema?
Alveoli stretch out of shape or rupture
Lungs lose their natural elasticity
Loss of the alveolar walls leads to decrease in elastic recoil leading to airflow limitation
Lungs lose their ability to absorb oxygen and release carbon dioxide
What are the causes of emphysema?
Smoking
Air pollutants
Respiratory infections
Genetics - alpha-1 antitrypsin deficiency (a protein that protects the lungs)
What are symptoms of emphysema?
Shortness of breath or dyspnoea
Chronic cough that produces mucus
Wheezing
Tightness in the chest
Fatigue
What is chronic bronchitis?
Infection causes Inflammation of the airways
What happens in chronic bronchitis?
What features does it have?
Infection causes airways to be inflammed
This irritation causes mucus to build up
The cilia become damaged and can’t move the mucus
Squamous epithelium thickens and blocks the airways causing breathing difficulty
The mucus contains pathogens and dirt that are stuck in the respiratory tract
What are the symptoms of chronic bronchitis
Cough
Production of mucus
Fatigue
Shortness of breath
Slight fever and chills
Chest discomfort
What causes chronic bronchitis?
Smoking
Air pollution
Dust or toxic gases in environment
Lung diseases (asthma, sinusitis, TB)
What is the treatment of COPD?
No cure but treatment involves helping symptoms and preventing it getting worse
Stopping smoking
Inhalers
Pulmonary rehabilitation - a special programme of exercise and education
Surgery or lung transplant (rare)
What are basal cells and function?
Type of epithelium
Differentiate into the other cell types to restore a healthy epithelial cells
How do the alveoli become damaged in emphysema?
Inflammation is caused by smoking as it attracts phagocytic cells to the alveoli
These cells produce elastase which break down elastin and other proteins in the alveoli
What happens if polyspermy occurs
If it happens the embryo doesn’t grow due to the imbalance of chromosomes
What does l-dopa do?
Increases dopamine in the presynaptic neurone to release in the post-synaptic neuron
What is the cell surface membrane of a skeletal muscle called?
Sarcolemma
