OTHER HALF (lectures 27-36) Flashcards
What is Vasoconstriction?
The contraction of smooth muscle in the arteriole walls; it increases blood pressure
What is Vasodilation?
The relaxation of smooth muscles in the arterioles, causes blood pressure to fall
- Nitric oxide is a major inducer
What are Baroreceptors?
Specialized nerve endings that respond to stretch of vessel wall indirect response to changes in BP
- Located in the carotid and aortic arch
What is the Renin-Angiotensin-Aldosterone system?
It is apart of a complex feedback circuit that functions in homeostasis
- drop in blood pressure near glomerulus causes the juxtaglomerular apparatus of the kidney to release the enzyme renin
- renin triggers the formation of the peptide angiotensin II
- Angiotensin raises blood pressure and decreases blood flow in the kidneys
- also stimulates the release of the hormone aldosterone, which increases blood volume and pressure
What are factors affecting blood pressure?
Diet: (salt, fat, cholesterol, alcohol)
smoking, obesity and type 2, diabetes, stress, low activity
Hypertension
How do you treat hypertension?
Non-pharmacological: lifestyle changes - diet, exercise, smoking, alcohol
Drug treatment: antihypertensives, reduce blood volume and reduce cardiac output
- Beta-blockers
- alpha-blockers
- mixed
-ACE inhibitors
What are cells in the innate immune system?
- Dendritic cells
- Macrophage
- Natural killer cell
- Neutrophil
- Basophil
- Eosinophil
What are cells in the adaptive immune system?
B cell, T cell
What are the two sides of an immune response?
Internal threat - autoimmune problem (disease; cancer, hepatitis, HIV, shingles)
External threat - allergic reaction (infection; bacteria, mold/fungus, parasites, viruses)
How are RNA viruses recognised?
They are recognized by nucleic acid detection and drive interferons
- Type -I interferons prepare local cells to avoid viral infection
(viruses try to subvert this)
What is viral sepsis and systemic inflamation?
Infection of the lung epithelium, increased vascular permeability and local inflammation.
- Lowered lung function and hypoxemia
- Acute anti-viral response ‘goes systemic’
- Increased coagulation, microcirculation problems, brain tissue hypoxia
What are the two checkpoints in the immune system to fight cancer?
- Ipilimumab
- Nivolumab
What are the side effects of checkpoint therapy in cancer treatments?
The checkpoints are not specific to tumor environment:
some side effects in include -
Thyroiditis, dry mouth, rash, vitiligo, myocarditis, pancreatitis, hepatitis neuropathy etc.
What is the link between inflammation and obesity?
- Fat tissue contains 50-60% macrophages and regulatory T-cells
- Apoptotic fat cells –> inflammatory factors released and M1- activated macrophage
- TNF-a and other inflammatory factors
- Inflammation recruits additional immune cells
- Inflammation causes fat tissue to become insulin-resistant
What is the difference between lean adipose tissue and obese fat tissue?
After weight gain the tissue becomes inflamed and there are pro-inflammatory molecules present
What are iNKT cells?
They are also known as Invariant natural killer T cells: restricted and conserved CDR3 region, Non-MHC-restricted, invariant/semi-variant
- They also produce IL-10 (a cytokine with anti-inflammatory properties)
What do iNKT cells do for the metabolism?
They positively regulate the metabolism
What do macrophages do for the brain?
They repair brain injury, but if the brain is injured again 1-2 later there will be no healing and lasting damage.
What are essential nurients?
Required materials that an animal cannot assemble from simpler organic molecules
What are the four classes of essential nutrients?
-Essential amino acids
- Essential fatty acids
- Vitamins
- Minerals
What is digeston?
The process of breaking food down into molecules small enough to absorb
What is mechanical digestion?
The chewing, or grinding, increases the surface area of food.
What is chemical digestion?
digestion splits the food into small molecules that can pass through membranes; these are used to build larger molecules
- the process of enzymatic hydrolysis splits bonds in molecules with the addition of water
What are the organs/parts required for digestion?
Tongue, oral cavity, salivary glands, pharynx, esophagus, liver, gallbladder, stomach, pancreas, small intestine, large intestine, rectum, anus
What occurs in the oral cavity?
Food processing begins in the oral cavity: oral cavity, pharynx, esophagus
steps:
1. saliva breaks down starch
2. Tongue helps to shape food for swallowing
3. pharynx opens the esophagus and the trachea
4. Esophagus connects to stomach, trachea leads to lungs
How does Saliva work?
saliva (exocrine secretion from salivary glands) contains mucus - mixture of water, salts, cells and glycoproteins and amylase, break down starch.
What are the layers of the digestive tract wall?
Generally:
1. Lumen
2. Submucosa
3. Mucosa
4. Muscularis externa
5. Serosa
What is the mixture of ingested food and gastric juices called?
it is called chyme
How are gastric juices produced? (steps)
- Pepsinogen and HCI introduced into lumen
- HCI converts pepsinogen to pepsin
- Pepsin activates more pepsinogen, starting a chain reaction
What is the first portion of the small intestine called?
it is called the duodenum
What happens in the first part of the small intestine also known as the duodenum?
The chyme from the starch mixes with digestive juices from the pancreas, liver, gallbladder and the small intestine itself
What does the pancreas produce?
It produces the proteases trypsin and chymotrypsin which are activated in the lumen of the duodenum
Where is bile made and stored?
It is made in the liver and stored in the gallbladder.
What does the hepatic portal vein do?
it carries nutrient-rich blood from capillaries of the villi to the liver, then to the heart and onwards to all organs
Why is the small intestine able to absorb so much nutrients?
this is because it is composed of villi and microvilli making its surface area extremely large, so it is able to absorb a lot, including water
What happens to fatty acids and monoglycerides?
Epithelial cells absorb them and recombine them into triglycerides, these fats are coated with phospholipids, cholesterol, and proteins to form water-soluble chylomicrons. chylomicrons are transported into lacteal, a lymphatic vessel in each villus.
What stimulates the production of gastric juices?
Gastrin does
Where is energy first stored in the human body?
First stored in the liver and muscle cells in the polymer glycogen, excess energy stored in fat adipose cells
What is the absorptive state?
- fed state
- glucose is plentiful and serves as major energy source
- Insulin is a major hormone of absorptive state
What is the postabsorptive state?
- Fasting state
- Endogenous energy stores are mobilized to provide energy
- Glucagon is major hormone of postabsorptive state
What regulates the breakdown of glycogen into glucose?
The hormones Insulin and glucagon.
What hormone triggers the feeling of hunger before a meal?
Ghrelin triggers the feeling, its is secret by the stomach wall
What are the effects of epinephrine and norepinephrine?
- Glycogen broken down to glucose; increased blood glucose
- Increased blood pressure
- Increased breathing rate
- Increased metabolic rate
- Change in blood flow patterns, leading to increased alertness and decreased digestive, excretory and reproductive system activity
What are the effects of mineralocorticoids?
- Retention of sodium ions and water by kidneys
- Increased blood volume and blood pressure
What are the effects of glucocorticoids?
- Proteins and fats broken down and converted to glucose, leading to increased blood glucose
- partial suppression of immune system (this is why glucocorticoid drugs are prescribed for autoimmune disorders e.g. allergies)
What diseases are linked to physical inactivity?
- CHD
- Stroke
- Cancer
- T2D
- Dementia
What are the benefits of exercise to multiple physiological systems?
Neurological:
LOWER -
- anxiety/depression
- Dementia
- Risk of stroke
HIGHER -
- cognitive function
Cardiovascular:
LOWER -
- mortality
- coronary artery disease
- blood pressure
Oncological:
LOWER -
- prostate cancer
- breast cancer
- bowel cancer
Musculoskeletal:
LOWER -
- Osteoporosis
- Falls
- Disability
How can physical activity be protective to the brain?
The more you exercise the more myokines that you produce which are anti-inflammatory and this produces cytokines like: IL-10 and IL-6
- These help with synaptic plasticity
- Neurogenesis
- Cognitive function
What are somatosensory receptors?
Mechanoreceptors
- cutaneous, proprioception, force
Thermoreceptors
- temperature
Nociceptors
- pain
Where are somatosensory receptors?
Skin - tactile, thermoreceptors, pain
Muscle - muscle spindle
Joints - Articular
What are the two classes of somatosensory receptors?
- Rapidly adapting
- Slowly adapting
What are examples of rapidly adapting tactile mechanoreceptors?
- Meissner’s corpuscles
- located in hands/feet
- touch, vibration
- rapidly adapting - Pacinian corpuscles
- high frequency vibration
What are examples of slowly adapting tactile mechanoreceptors?
- Merkel’s receptors
- pressure - Ruffini’s corpuscles
- stretching of skin
What are receptive fields determined by?
receptor type, distribution density, activation threshold, duration of activation, adaptation, central convergence ratio
What are the parts of the sensory motor system?
Cortical areas:
- primary motor cortex M1
- premotor cortex
- Supplementary motor area
- S-I and S -II
Subcortical areas:
- cerebellum
- Basal ganglia
What is a command neuron?
The term was introduced by Wiersma, studying neurons with long axons in crayfish
- when stimulated these neurons evoked movement, the pattern of which was not coded in their sequence of spikes
- Neural decision-making
What was found in command neurons in mice?
In mice it was found that brainstem neurons were found to be responsible for stopping locomotion
what are characteristics of the basal ganglia?
- largest sub-cortical structures in the forebrain
- paired nuclei
- no direct sensory inputs
- no direct motor outputs
- disease of the basal ganglia: primarily movement disorders, neuropsychiatric symptoms, related to addiction, learning and memory
*so basically everything
What is the Basal ganglia motor loop?
It results in the activation of the supplementary motor area (SMA) before and during moving
What are the symptoms of Parkinson’s disease?
- Tremor
- Rigidity
- Akinesia/Bradykinesia (weakened contribution of SMA prior to movement)
- Posture
What do mirror neurons do?
they help us observe actions of others, helpful to the survival of species.
What is the definition of pain?
An unpleasant sensory and emotional experience associated with, or resembling that associated with actual or potential tissue damage.
What is acute pain?
It is essential to avoid injury
-withdrawal reflex is observed across species
What is chronic pain?
- pain that lasts 3-6 months after initial injury
- pain experienced is no longer beneficial for survival
What are different pain pathways?
Spinothalamic tract
* Spinoparabrachial tract
* Spinoreticular tract
* Spinomesencephalic tract
What is the gate control theory: Melzack and Wall (1965)?
- There are unlimited c fibers and small diameter A-delta are stimulated by injury and convey impulses to transmission cells in the spinal chord (T)
- T-cells receive input from large A-beta fibers
- T-cells receive inhibition from interneurons
- descending pathways influence inhibitory interneurons
What does the stimulation of PAG do?
it induces analgesia, which is pain relief without the loss of consciousness
What are some antinociceptive mechanisms of the brain?
- Thalamic gate attention control, deconditioning, relearning
- Descending inhibition
- Gate control
- Long term depression
- Adaptation
- fatigue
What does Antinociceptive mean?
it means the action or process of blocking painful stimulus
What are some Pronociceptive mechanisms of the brain?
- Reorganization
- conditioning
- Catastrophizing
- Descending facilitation
- Central sensitization
- Long-term potentiation
- Peripheral sensitization
What does Pronociceptive mean?
To carry or amplify the signal induced by the stimulus
What are the different types of memory + how long do they last?
- Sensory (milliseconds to seconds)
- Short-term and working (seconds to minutes)
- Long-term nondeclarative (minutes to years)
- Long-term declarative (minutes to years)
What is the Atkinson and Shiffrin model of memory?
It says that sensory information enters the information-processing system and is first stored in a sensory register.
- Then items are selected (via attentional processes are moved into short-term storage and with time can be moved to long-term
What is the Baddeley and Hitch model of memory?
Three part working memory system, central executive that controls two subordinate systems
1. the phonological loop, encodes info acoustically in working memory
2. visual sketch pad, encodes info visually
How are the hippocampus and amnesia connected?
A person by the initials H.M. suffered from epilepsy, surgery in 1953 (bilateral medial temporal lobe removed
- he was left with normal IQ but the surgery left with severe anterograde amnesia
- short-term memory was still intact
What is plasticity?
Neuronal plasticity describes the ability of the nervous system to be modified after birth
- synaptic plasticity means the strengthening or weakening of synaptic junctions
What is Anisomycin?
It is a protein synthesis blocker
