anatomy

coronal (frontal) plane

separates anterior and posterior of the body

sagittal (longitudinal) plane

separates left and right of the body

transverse (axial) plane

separates superior and inferior of the body

embryonic stage (first 8 weeks)

fertilisation, early cell division, implantation and organ formation

early cell division

zygote travels to the uterus, dividing rapidly to form a morula, then a blastocyst

implantation

blastocyst attaches to the uterine lining; inner cells will become the embryo and the outer layer will form the placenta

organ formation

embryo develops three distinct layers that form all the body tissues. the neural tube, heart and major organs begin to form; the heart begins to beat around weeks 5-6

fetal stage (9 weeks to birth)

growth and maturation, external features, motor skills, brain development and organ function

brain development

the brain develops and forms major sulci and gyri (grooves and ridges), and synapses begin to form

organ function

bone marrow takes over the productin of RBCs

five main body cavities

• cranial

• spinal

• thoracic

• abdominal

• pelvic

central nervous system (CNS)

brain and spinal cord

peripheral nervous system (PNS)

cranial, spinal and peripheral nerves

neurones in the PNS

sensory and motor neurones

pancreas acinar cells

produce digestive enzymes

islets of langerhans

secrete hormones

lymphatic system functionb

tissue drainage, absorption in the small intestine and immunity

meninges of the brain

• dura mater

• arachnoid

• pia mater

cerebrospinal fluid (CSF)

provides a cushion between the brain and the skull

blood-brain barrier

structure that lines blood vessels in the CNS, formed by endothelial, pericyte and astrocyte cells, only allowing some compounds to reach the brain. exchanges of information between astrocytes and neurons make it more restrictive/permeable

fissure

large furrow that divides the brain into lobes and two hemispheres (longitudinal fissure)

three main parts of the brain

• cerebrum

• cerebellum

• brain stem

four lobes of the brain

• frontal

• parietal

• occipital

• temporal

cerebral cortex

outer layer of the cerebrum that takes part in complex cognitive processes

basal ganglia

group of nuclei in the brain involved in coordinating movement and regulating voluntary motor control

thalamus

brain structure that relays sensory information and plays a role in regulating sleep and consciousness

hippocampus

region of the brain involved in the formation of new memories and spatial navigation.

amygdala

emotional processing center in the brain associated with fear and pleasure responses

hypothalamus

regulation of body function

synaptic boutons

axon branches out at the end to send impulses to many different neurones

resting potential

inside of the cell is relatively negative to the outside and the ion channels are closed

action potential

a stimulus causes opening of ion channels, movement iof ions creates a depolarising current which triggers the appearance of an action potential which travels down the axon

two types of post-synaptic potential

excitatory or inhibitory

glial cells

provide the neurons with physical support, control nutrient flow and are involved in phagocytosis

astrocytes

provide physical support, remove debris (phagocytosis) and transport nutrients to neurons

microglia

defensive cells involved in phagocytosis and immune function

oligodendrocytes

provide physical support and form the myelin sheath around axons in the brain

satellite cells

surround neuron cell bodies in the PNS

Schwann cells

surround peripheral nerve fibres and form myelin sheaths; vital to regeneration of damaged peripheral nerve fibres

divisions of the PNS

• somatic nervous system

• autonomic nervous system

somatic nervous system

responsible for carrying sensory and motor information to and from the CNS (sensory/afferent neurones and motor/efferent neurones)

divisions of the autonomic nervous system

• sympathetic nervous system

• parasympathetic nervous system

sympathetic nervous system

coordinates the fight or flight response

parasympathetic nervous system

coordinates the calming down response to return the body to a normal resting state

what happens to nerve cells during ageing?

the shrink - brain function is affected but still there

Alzheimer’s cause

neurofibrillary tangles and amyloid plaques

Parkinson’s causes

Lewy bodies/neurites

divisions of the human skeleton

• axial

• appendicular

long bones

longer than the are wide, with a shaft and two ends (femur, tibia, radius)

short bones

same length and width (carpals and tarsals)

flat bones

thin and broad bones when extensive organ protection or broad surfaces of muscle attachment are required (sternum, ribs, roof of the skull)

irregular bones

complex shapes - short, flat, notched or ridged surfaces (vertebrae, hip bones)

sesamoid bones

small, flat bones shaped like a sesame seed; they develop inside tendons and may be found near joints at the knees, hands and feet (patella)

sutural bones

small, flat and irregularly shaped bones; found between the flat bones of the skull

compact (cortical) bone tissue

hard outer layer that is dense, strong and durable

osteons

cylindrical units of compact bone that appear as concentric circles, aligned in the same direction to help the bone resist breaking or fracturing

cancellous (trabecular) bone tissue

network of trabeculae or rod-like structures; lighter, less dense and more flexible than compact bone

red bone marrow

produces blood cells, is found between the trabeculae of cancellous bone tissue e.g. the femur and the ileum

osteoblasts

responsible for bone formation - they do not divide, they synthesise and secrete the collagen matrix and calcium salts. this calcifies and traps the osteoblasts, turning into an osteocyte

osteocyte

the primary cell of mature bone; they maintain the mineral concentration of the matrix via the secretion of enzymes (also do not divide)

osteogenic cells

stem cells with high mitotic activity, differentiate into osteoblasts; important in the repair of fractures

osteoclasts

responsible for bvone resorption or breakdown, originating from monocytes and macrophages (white blood cells)

intramembranous ossification

development of bone from fibrous membranes (involved in formation of flat bones)

endochondral ossification

replacement of hyaline cartilage with bone (cartilage serves as a template to be complete replaced by bone) - involved in formation of bones at the base of the skull and long bones

gross anatomy of mature bone

two parts; diaphysis and epiphysis, meeting at the metaphysis

medullary cavity

hollow region in the diaphysis filled with yellow marrow

endosteum

delicate membranous lining of the medullary cavity where bone growth, repair and remodelling occur

periosteum

fibrous membrane on the outer surface of the bone, containing blood vessels, nerves and lympathic vessels that nourish compact bone

epiphyses

the wider sections at each end of the bone, filled with spongy bone which is filled with red marrow

articular cartilage

a thin layer of cartilage that covers the epiphyses, that reduces friction and acts as a shock absorber

epiphyseal plate

area of growth in a long bone - chondrocytes on epiphyseal side divide, one remains undifferentiated near the epiphysis and one cell moves towards the diaphysis. these cells mature and are destroyed by calcification - replacing cartilage with bone on diaphyseal side, resulting in bone lengthening

bone healing

haematoma, inflammation (fibroblasts and osteoblasts migrate to form fibrocartilaginous callus), cartilage of callus replaced by trabecular bone and remodelling by osteoclasts and osteoblast occurs

fibrous joints

no joint cavity, connected via dense connective tissue consisting mainly of collagen - immovable joints (skull bones are connected by fibrous joints called sutures)

cartilaginous joints

bones are entirely joined by hyaline cartilage or fibrocartilage, generally allow more movement than fibrous joints but less than synovial

synovial joints

found between bones that move against ech other, such as limb joints - allow the most movement

synovial fluid

lubricates the joint, reducing friction between bones and allowing for greater movement

synovial lining

membrane that lines the joint and secretes synovial fluid

ligaments

connect bones together - tough, elastic bands of connective tissue that limit joint movement

tendons

connect muscle to bone - tough connective tissue on each side of the joint

bursa

fluid-filled sacs between bones, ligaments or other nearby structures - cushion the friction in a joint

pivot joints

synovial joints that allow bone rotation around another bone

hinge joints

synovial joints that allow flexion and extension in one plane

saddle joints

synovial joints that permit the same movement as condyloid joints and combine with them to form compound joints

planar/gliding joints

synovial joints that only allow sliding movement

condyloid joints

synovial joints that perform flexion, extension, abduction and adduction movementsand allow for circumduction

ball-and-socket joints

synovial joints that allow all movements except gliding

pivot joints and example

rounded end of one bone fits into a ring formed by another (between first and second vertebrae)

hinge joints and example

slightly rounded end fits into the hollow end of another bone - one moves while the other remains stationary (elbow)

saddle joints and example

concave and convex portions of bone that fit together, allow angular movements and greater range of movement than condyloid joints (thumb joint)

planar joints and example

articulating surfaces that are flat or slightly curved - range of motion is limited in these joints and does not involve rotation (carpals and tarsals)

condyloid joints and example

oval-shaped end of one bone fitting into the hollow of another bone - sometimes called an ellipsoidal joint - allows angular movement along two axes (wrist and finger joints)

ball-and-socket joints and example

rounded-ball like end of one bone fitting into a cuplike socket of another (shoulder and hip joints)

skeletal muscle

attaches to bones or skin to control locomotion and any movement that can be consciously controlled - long and cylindrical in appearance, striped or striated under a microscope

three connective tissue layers in skeletal muscle

• epimysium

• perimysium

• endomysium

epimysium

connective tissue sheath surrounding each muscle

perimysium

connective tissue surrounding the bundle of muscle fibres called the fasciculus

endomysium

connective tissue surrounding each individual muscle cell or fibre within the fasciculus

sarcolemma

plasma membrane of a skeletal muscle fibre - site of AP conduction

sarcoplasm

cytoplasm of the skeletal muscle fibre

microfibrils

long cylindrical structures that lie parallel to the muscle fibre