1103 Exam Flashcards
what is Anthropometry
the measurement of body size, weight and proportions.
what is body composition
Measurement of what proportion of the body is made up of: Bone, fat, muscle, fat mass + water
what is fat- free mass (FFM)
Protein, mineral+ water
Essential fat= minimum amount of fat needed for normal physiological functions (3-5% for males + 8-12% for females)
Non- essential fat= subcutaneous fat (under skin) and visceral fat (around organs)
What are the methods of partitioning
Direct= most accurate, requires dissection+ chemical analysis of a corpse
Indirect= something other than %BF is measured and used to make an assumption
Doubly indirect partitioning=
Use an indirect measure (assumption 1)
Apply that result to a regression equation (assumption 2)
BMI
based off the principle that height is proportional to weight
Used to estimate degree of obesity in large population studies, and is not useful to athletes
BM (kg)/ Height (m^2)
Waist- to- hip- ratio
Provides indication of disease risk
Waist (cm)/ hips (cm)
Increased risk of disease when WHR >0.80 in women and >0.90 in men
Waist= narrowest point/ midpoint between the lowest rib+ top of the hip bone (iliac crest)
Hips= feet together, at level of greatest gluteal protrusion
Densitometry
Based on the principle that fat is less dense and more buoyant than lean tissue.
Body density (Db) is calculated using body mass (kg) and body volume (L).
Formula to estimate body fat: % Fat = 4.950/Db - 4.500.
Techniques:
2C model (indirect).
Fully submerged in water or placed in an air chamber to measure volume displaced.
Lung air volume measured using helium.
Key Assumptions:
Fat mass (FM) and fat-free mass (FFM) are constant.
Fat: 90% triglycerides with a stable density.
Fat-free mass: Muscle and bone densities vary based on factors like age and lifestyle
Dual- energy X- ray absorptiometry (DEXA)
- 3- C model
- low energy X-rays are passed through the body which are absorbed differently by bone and tissue.
- Estimation of FM and FFM is based on assumptions regarding hydration, potassium content, or tissue density.
- Provides data on whole body and regional (e.g., arms, legs and trunk).
Sources of error
- Assumptions of %FM is based on ‘trunk thickness’.
- Hydration and nutritional status (e.g., glycogen).
- Body composition estimation algorithms are not developed on athletes.
Advantages: High degree of accuracy, quick (5-20 minutes), noninvasive, includes bone mineral density, segmentation of body part (injured athletes)
Disadvantages: Expensive Need a referral from GP Requires a trained technician Small radiation exposure
Bioelectrical impedance analysis (BIA)
FFM =TBW/0.732
FM= body mass –FFM
- 4C model: doubly Indirect.
- The BIA provides a measure of total body
water (TBW), to provide estimate of FFM.
- Single vs multi-frequency.
- Based on the principal that fat is less conductive than lean tissue.
- Most TBW is found in FFM
Skinfold Calipers
- 2C model, double indirect
- Measured double thickness of skin+ subcutaneous fat
- Using marked anatomical landmarks
- %BF is based on measurements of subcutaneous fat mass
- Skinfold (mm) → body density → %BF
Advantages: Quick, cheap, portable, relatively accurate
Disadvantages: Takes practice and skill, invasive, and does not take into consideration fat distribution
Somatotyping
Describing the phenotype of a human physique of a number of traits that related to body size and composition.
➢ Endomorphy: describes the relative degree of adiposity , roundness, softness and relative volume of the abdominal trunk.
➢ Mesomorphy: Describes the relative muscle mass.
➢ Ectomorphy: Describes the relative slenderness of the body.
Measurements you need: Height (cm), Weight (kg), Triceps, subscapular, supraspinal, calf skin fold (mm), Width of elbow and knee joint (cm) , Circumference of flexed bicep and calf muscle (cm)
Enter values into equations to get a three-numeral rating based on each somatotype.
▪ A rating of 1 to 7 is given, where 1 is the minimum and 7 is the maximum.
what are the 4 Receptors for feedback
Thermoreceptors
Chemical receptors (pH levels, Ions, Glucose levels)
Photoreceptors (in the eye to control iris diameter)
Osmoreceptors in the brain (regulation of water balance)
signal transduction effects
- Changes to permeability, transport properties, or electrical state of the plasma membrane
- Altering metabolism
- Changing proliferation rate/ growth
- Causing secretion of other molecules
- Inducing contractions/ other physical activities
endocrine signaling
Production of a hormone from a gland that travels within the blood stream to other organs
Generally have systemic effects E.g adrenaline= increase HR= increase energy production etc.
paracrine signaling
Secretions that act only on neighboring cells
Prominently featured in development E.g development of arm cells with signal to adjacent cells to develop into hands
autocrine signaling
Signaling molecules produced by the cell affect the cell itself
Occurs in certain immune cell activations
Common in some cancers which secrete HGH to drive their own proliferation
epithelial tissue
Lines all body surfaces, both internal and external
Depending on location, structure and arrangement of the cells can vary greatly
Lung tissue is thin= gaseous exchange, whereas esophagus is thick to provide protection
Limbic Lobe
- Learning+ memory
- Included hippocampus= critical for learning
- Emotion processing
Brain Stem
- Involved in the control of: CV system, Respiratory, alertness/ awareness, pain sensitivity control
- Damage= life threatening
Pituitary Gland
- Direct access to peripheral blood circulation
- Secretes many hormones- important for growth/ regulation
- Anterior+ posterior divisions
Anterior
-HGH, Gonadotrophs, thyroid stimulating hormone, corticotropin
Posterior
-Vasopressin, oxytocin
astrocytes
- Subset of neuroglia
– Neuroglia outnumber neurons 3:1 in the cortex
– Astrocytes account for 20 – 40% of all glial cells - Has many roles in supporting brain/ SC
Neurovascular coupling
- Entry of substances onto the brain= tightly controlled by ‘blood- brain barrier’
– Important in maintaining controlled environment
– Prevents entry of pathogens
microglia
- Surveying= Move through brain to detect damage/ invasion- can include pathogens, plaques, DNA, fragments or dead cells
- Can help regulate synapse number by eliminating un- used pathways
- Phagocytosis= Once the microglia find they become activated and engulf invading pathogens, dead cells and debris
- Secretion of inflammatory Mediators= activated by cytokine IFN-y to fight infection
what are the 2 main neurotransmitters
Noradrenaline= for sympathetic
Acetylcholine= for parasympathetic
what is an action potential and how does it work?
Propagation of an electrical signal along a neuron
- We refer to the inside relative outside- therefore inside is more negative than outside of the cell
Depolarisation= membrane becoming more positive (less polarised)
Hyperpolarisation= membrane becomes more negative
- The potentials on each side are largely balanced due to distribution of sodium, potassium, chloride and negatively charged proteins
Resting membrane potential pump
The pump has two stable configurations
- The pump binds an ATP molecule and 3 intracellular Na+ ions
- ATP is hydrolysed which phosphorylates the pumps and changes its shape
- This new configuration has a low affinity for Na+ so they are released
- Two extracellular K+ ions are bound which dephosphorylates and reverts it to the original shape
- The original configuration has a low affinity for K+ so they are released
What comprises a sensory system
receptor- detects a stimulus
neural pathway- signal must be carries from receptor to brain
CNS processing- integrates sensations in the brain
Touch
Pressure that moves skin forces open ion channels in the skin-graded potential
Types of Touch receptors:
Merkel’s= sustained pressure
Meissner’s= change in texture
Ruffini= Skin Stretch
Pacinian= Deep Pressure
Hearing
- Sound energy moves as waves of compressed air molecules
- outer+ middle ear function to amplify sound
- ear drum is connected to ossicles (3 tiny bones), which function to convert sound energy into mechanical energy
Anatomy of the eye
Cornea: Contributes to refractive power which focuses light to the retina
Iris: Controls amount of light entering the eye
Lens: Works with cornea to focus light into retina, Fine tunes focus
Retina: Layer of photoreceptors, responsible for turning light energy into electrical
Fovea: Specialised area of the retina with very high acuity
Cones: Detects colour, active only in bright light
Rods: Active in dark conditions, mostly B/W
Receptors in the eye
Light energy triggers the conversion of 11-cis retinal to all trans- retinal
- In the dark, the retinal cells are consistently depolarising and releasing neurotransmitter onto the bipolar cells
- These cell inhibit the ganglion cells which lead to the brain
- Thus, in the light, the photoreceptor stops releasing neurotransmitter to bipolar cells which stops the inhibition of the ganglion cells
Detecting the five primary tastes
Salty
- Acts on membrane channel that allows salt ions to flow through
- Results in depolarisation of cell+ release of neurotransmitters
Sour
- Acts on membrane channel that allows H ions to flow through
- Causes closure of leaky K+ channels= depolarisation of cell+ release of neurotransmitters
Sweet
- Acts on a G- Protein coupled receptor causing signaling cascade resulting in closure of leaky K+ channels= depolarisation of cell+ release of neurotransmitters
Bitter
- Also acts on G- protein coupled receptor leading to signaling cascade= opening of calcium channels= depolarisation of cell and release of neurotransmitters
Umami
- Glutamate receptors are G- Coupled protein receptors which cause signaling cascade resulting in opening= depolarisation of cell and release of neurotransmitters
what is the purpose of bone
Structural support
Protects internal organs
Allows movement by providing site for muscle attachment
Reservoir for mineral homeostasis
Provides environment for hematopoiesis
What are the 5 types of bone
long, short, flat, sesamoid, irregular
Red vs yellow bone marrow
The proportion of bone marrow changes with age, being totally red at birth and gradually accumulating more yellow with age
Red Bone Marrow
- Contains high numbers of hemopoietic stem cells (differentiate into red and white cells + platelets)
- Located in central skeleton and ends of large bones
Yellow Bone Marrow
- Contains high numbers of adipocytes
- Primarily found in cavity of long bones
what are osteoclasts
Bone ‘eating’ cells
Secrete H+ ions to acidify and break down underlying bone
synapse- neurotransmitter release
Synampse= Point of communication b/w neurons , Largely self- contained
Neurotransmitter release
1. When the action potential reached the axon terminal it opens voltage gated calcium channels
- Calcium entry triggers vesicles containing neurotransmitter to be released into the synapse
- The neurotransmitters bind to receptors on the neighbouring dendritic spine and cause a graded potential
Neurotransmitter release= Very slow compared to action potential, Only a single synapse between our outer+ lower motor neurons
what makes up the olfactory epithelium
Basal cells: Stem cells that give rise to receptor cells
Supporting Cells: Mechanical support for olfactory receptor neurons, secretions contribute to mucus layer
Bowman Gland: Contributes to serous secretions to mucus layer
Olfactory Receptor Neurons: Terminal contains 10-30 non- motile cilia which contain receptors to detect odours
Osteoblasts
Bone ‘building’ cells- form the major component of bones
Secrete hydroxyapatite
As the osteoblasts secrete minerals, they become encased immobile, transitioning to osteocytes
These osteocytes then form tight junctions which isolate bone from extracellular fluid
Classification of joints
Fiborous
-No movement
-Bone that have fused together during development
-Composed mainly of collagen
Cartilaginous
-Some movement
-Connected entirely by cartilage
Synovial
-Freely movable
-Feature a joint cavity filled with fluid
Sliding Filament Model
Ca binds to troponin, moves tropomyosin off actin, allowing myosin to bind
Globular heads at opposite ends of the thick fillament attach to the thin fillament and pull inwards
This shortens the sarcomere and contracts the overall muscle
Crossbridge Cycling
- Myosin head binds to the actin filament
- Power stoke phase occurs. Here the myosin head pivots and pulls on the actin filament
- ATP binds to myosin head, detaching it from actin filament
- Myosin head hydrolyses the ATP molecules, resetting itself for another cycle
Recruitment
Recruitment of more muscle fibres= more force
Activated in order from small -> large as this allows the grading of the amount of force to perform task
Summation
While the size of the action potential can’t be changed, the frequency at which they fire can be
If a second action potential fires before the first has a chance to relax, the contractions build upon one another
This occurs because:
1. Muscle contracts from a higher baseline
2. There is still calcium left within the cell which increases the amount of cross bridges
Antigens
Molecular structures that can be recognised by their physical shape by ‘antigen recognition structures’ on the surface of immune cells (WBCs)
innate immunity
Non- specific
Very fast
Non- adaptive (no –memory)
Natural barriers, secreted molecules, phagocytosis, cell lysis
Recognition is via
-Limited Number of pathogen pattern receptors (antigen recognition)
-Receptors of chemokines, cytokines+ complement
Adaptive Immunity
More specialised than innate
Works only after 2-10 days
Based on antigen- recognition molecules that can distinguish foreign antigens
Distinguishes self from non- self
B- Cells
produced in bone marrow
Memory
Naïve, effector, plasma, memory
Immunoglobins
Humoral immunity
T- Cells
produced in bone marrow+ Thymus
Naïve, effector (cytotoxic, helper, regulatory), memory
MHC proteins
Cell mediated immunity
What are the 3 tissues of the immune system?
Primary lymphoid organs
- Organs and tissues where lymphocytes are produced
Secondary lymphoid organs
-Organs and tissues where lymphocytes:
-Have contact with foreign antigens
-Undergo clonal expansion
-Mature into effector cells
Lymph vasculature
-Vessels that collect and circulate lymph fluid
Thymus
Pre- T cells from bone marrow migrate ti thymus where they are differentiated into mature, naive T-cells
Most active during infancy
After puberty, thymus undergoes involution
Spleen
Sits in upper abdomen near the stomach
Filters blood and removed dying RBCs
Removal of opsinised bacteria
Removal of any self- reactive cells that have escaped the bone marrow
