body systems 1-4

body systems

anatomy and physiology

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what is anatomy

anatomy is the study of internal and external body structures, it focuses on location, structure and the relationship between body parts. Human anatomy can be divided into gross anatomy and microscopic anatomy. Click the images to learn more about each.

what is physiology

Physiology asks how function happen, what makes us work? These functions ar emore complex than simply studying anatomy and so there are more divisions of the study. cellular physiology organ physiology systemic physiology pathological physiology

A physisian will use a range of techniques to assess a person. looking at anatomical, chemical and psychological signs and symptoms as well as physiological ones.

levels of understanding/organisation

tissue level

cellular level

chemical level

when a group of cells come together to preform specific functions this is know as a tissue which is then studdied at this level.

individual cells are made of several organelles, each of which playing a part to ensure the cell functions correctly.

the shape of molecules is often very complex, and even small changes affect the function. This is seen clearly in proteins where the shape of the molecules affect the active site of the protein

levels of understanding/organisation

organ level

organ system level

organism level

groups of organs can then come together and interact. This is an organ system, like the cardiovascular system.

two or more tissues working together for a specific function is considered an organ like the lungs or the liver.

The human as a whole individual life form is the organism. All previous levels must be fully functioning for the organism to be healthy.

body fluids and membrane transport

plasma membrane

• made of a phospholipid bilayer with proteins intersperced within, around 5nm thick
• many proteins to regulate movement of solutes and help control intracellular environment. Maintainence includes uptake of nutrients, exporting waste, regulating ions, pH, cell volume, p.d. and osmolality
• Channel proteins allow a type of molecule to undergo facilitated diffusion straight into or out of the cell down their concentration gradient
• carrier proteins also move molecules down their concentration gradient but in three different ways. Faciliatator/uniport poriens change shape to allow one molecules to travel in one direction. Cotransporters/symport proteins allow two different molecules to move in one direction. Exchangers or antiport proteins move two different molecules in two different directions
• Pumps require energy to actively transport one molecule at a time against their concentration gradient.

capillary endothelium

regulation of pressure and osmolality

structure

ion and protien regulation

water distribution between the ISF and the plasma is decided by two kinds of pressure. Hydrostatic pressure would have water moving out to the ISF, but the osmotic attractiveness of proteins stuck in the plasma means the colloid osmotic pressure has water moving into the plasma

- very thin layer of cells- hihgly permeable (leaky) in most areas of the body, the brain is an exception - basement membrane acts as a filter - regulates the interstitial fluid

small ions and organic solutes are approximately equal concentrations in the ISF in comparison to the blood plasma, but there are far more proteins in the plasma because theyre to big to cross the basement membrane.

epithelia

epithelial cells are found covering both the internal and external surfaces of organs and tissues. They act as a protective barrier controlling what is absorbed and what is secreted. They are well suited for this role due to the tight junctions between cells and the abundance of transporter proteins. The apical membrane is the side facing into a lumen and the basolateral membrane is the opposite.

Homeostasis

the regulation of a consistant internal enviroment through feedback loops

positive vs negative feedback

there are two types of feedback loops which help maintain homeostasis:

positive feedback

negative feedback

positive feedback is rarer because it requires an external stimuli to end. The increase of a molecule eventually causes its own increase

maintains a variable around a set point. The increase of one molecule eventually causes a decrease of the same molecule

control systems

There are two main control systems in the human body. The endocrine system relies on hormones, it is a slower change system resulting in long term effects. The nervous system uses electrochemical signals to send more immediate and short term changes.

the nervous system is separated into several divisions.

nervous system

Epithelial cells

epithelia cell basics

epithelia cover surfaces and line tubes and cavities, they also form glands. This means that they protect areas, control permeability and sometimes provide sensation. Cilia are classified through their shape and the number of cell layers in the most superficial level. Overall there are four important characteristics of epithelium cells:

attachment

avascularity

polarity

regeneration

classifications of epithelial cells

intercellular juntions

desmosomes

strong connections joing adjacent cells, desmosomes are resistant to twisting and stretching.

hemidesmosomes

anchor the cell in position by binding to the basement membrane

tight junctions

on the exposed (apical) side of the cell, cell membranes are bound together by proteins.

gap junctions

connexons (proteins) hold cells together but have a small passageway in them allowing the movement of small molecules and ions

connective tissue

connective tissue consists of cells within an extracellular matrix. Fibroplasts are the cells which synthesise this matrix which is made of ground substance, tissue fluid and fibres. The function of this tissue includes providing framework, transporting fluids and solutes, protecting organs and storing energy in the form of triglycerides.

specialised connective tissue

blood

cartilage

bone

loose (areolar) connective tissue

areolar tissues is the least specialised kind of connective tissue proper. It has an open framework. It has a variety of cells but ground substance provides most of the volume, it also absorbs shock. This tissue forms a layer separating the skin from deeper structures. Its loose structure allows for distortion without damage and elastic fibres allow it to have lots of independant movement.

dense irregular connective tissue

Alayer of this connective tissue gives the dermis its strength, this is because there is little ground substance but lots of haphazardly arranged collagen fibre bundles. It is also resistant to stretching and distentsion which is why it form protective capsules around organs like the kidneys

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dense regular arranged connective tissue

collagen fibres arranged in regular parallel rows make up the majority of the volume of this tissue. This means there is little ground solution and few cells. This type of tissue is found in tendons and ligaments

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muscle tissue

Muscle tissue produces movement as it is specialised for contraction. There are 3 types of muscle tissue but all have contractile elements, many mitochondrion and they are all elongated parallel to the axis of contractions

types of muscle tissue

skeletal muscle

cardiac muscle

smooth muscle

• found in heart wall
• helps circulate blood and maintain bp
• branched fibres
• striated
• 1/2 central nuclei
• intercalculated discs

• moves and stabilises the skeleton
• forms sphincters in the digestive and urinary tracts
• is involved in respiration
• long, cylindrical cells
• striated
• multinucleated

• found in the walls of organs, blood vessels and airways
• controls GI movement
• alters diameter of airways and blood vessels
• short, spindle shaped cells
• single centrally located nucleus

keratinised stratified squamous

Flat surface, oval shaped nuclues, many layers, keratin, function = protective, waterproof barrier, location = skin

simple squamous

• Flat cells
• oval shaped nuclie in thickest part of cell
• major function = the exchange of gases and nutrients
• location = blood vessels and alveoli

Gross anatomy

study of larger structures

Gross anatomy studies larger structures and therefore does not need a microscope. There are several catagories of gross anatomy, some are listed below:

• surface anatomy (body surface)
• regional anatomy (head, trunk, legs etc)
• sectional (uses cross sections of prgans and tissues)
• systemic (studies organ systems like cardiovascular or skeletal)

simple cuboidal

• square cells
• round nuclei
• one layer
• major function = secretion and absorbtion
• location = kidney tubules and glands

psuedostratified ciliated columnar cells with goblet cells

• tall cells
• appears tratified as some dont reach free surface
• modifications = cilia and goblet cells
• function = mucociliary escalator
• location = trachea and large respiritory airways

simple columnar

• tall cells
• basally located, oval nuclei
• major function = absorbtion and secretion
• location = GI tract
• Surface adaptation = microvilli

non-keratinised stratified squamous

• flat surface cells with oval shaped nuclie
• many layer
• major function = protection, barrier
• location = oral cavity, oesophagus

microscopic

Studying some areas of anatomy requires microscopes. This study is split into two areas.

• histology, is the study of tissues (groups of cells)
• cytology studies individual cells

sympathetic

fight or flight

the sympathetic nervous system is associated with a state of flight or fight. It sends signals to increase heart rate, increase breathing rate, slow digestion etc. The eurons flow from the thoracic and lumbar section of the spine.

• short preganglionic fibres
• transmits ACh at the ganglion
• long postganglionic fibres
• transmits norepinephrine at the effector

parasympathetic

rest and digest

the parasympathetic nervous system is associated with a bodily state of rest, this means this it sends signals to lower heart rate, increase digestion rate and so on. Neurons in the parasympathetic nervous system stem from the cranial and sacral part of the spine

• long preganglionic neurons
• transmits ACh at the ganglion
• short post ganglionic neuron
• transmits ACh to the effector