ACC DHUBS1 Weeks 1-3 Summary

Vocabulary flashcards covering basic medical terminology, cell structures, body systems, embryology, tissue types, and the nervous system based on DHUBS1 Weeks 1-3.

Cranial

Toward the head; for example, the cranial nerves are in the head.

Superior

Above.

Inferior

Below.

Medial

Toward the midline.

Lateral

Away from the midline.

Proximal

Toward the point of attachment of a limb to the trunk.

Distal

Away from the point of attachment of a limb to the trunk; for example, the fingers are distal to the wrist.

Superficial

At, near, or relatively close to the body surface; for example, the skin is superficial to underlying structures.

Deep

Toward the interior of the body; farther from the surface; for example, the bone of the thigh is deep to the surrounding skeletal muscles.

Posterior or Dorsal

The back surface of the body.

Anterior or Ventral

The front surface or belly side of the body.

Caudal

Toward the tail; in humans, this refers to the coccyx.

Coronal or Frontal plane

A vertical plane that divides the body into front and back sections.

Sagittal plane

A vertical plane that divides the body into left and right sections.

Transverse or horizontal plane

A plane that divides the body into top and bottom sections.

Abduction

Movement away from the midline.

Adduction

Movement toward the midline.

Tissue

A group of cells joined together that carry out a similar function.

Organ

Formed when tissues of similar but not identical function are joined together to carry out a common goal, such as the heart pumping blood.

Organ system

A number of different organs carrying out the same broad function, such as the heart and blood vessels forming the cardiovascular system.

Integumentary System

Major organs include skin, hair, sweat glands, and nails; functions to protect against environmental hazards and help regulate body temperature.

Skeletal System

Major organs include bones, cartilage, and ligaments; functions to provide support and protection, store calcium, and form blood cells.

Endocrine System

Major organs include pituitary gland, pancreas, gonads, and thyroid; functions to direct long-term changes, adjust metabolic activity, and control development.

Sex cells (gametes)

One of two classes of cells in the body, specifically for reproduction.

Somatic cells

A class of cells including all cells of the body except sex cells.

Ligands

Cell signalling molecules.

Receptors

The location on the cell where ligands attach to translate a signal.

Lock and key effect

The mechanism by which only certain cells respond to a specific ligand because the ligand is tailored to fit a specific receptor shape.

Ion gated channels

A plasma membrane type where a ligand attaches to a receptor, opening a channel for ions to pass into the cell.

Intracellular receptors

Receptors activated by lipid-soluble substances, such as steroids, which pass directly through the cell membrane.

Capacitated

The process where chemical reactions in the zona pellucida of the ovum break down the acrosome of the sperm.

Zygote

A single fertilised cell formed at day zero.

Morula

A solid ball of cells formed on days 3-4 post-fertilisation.

Blastocyst

A hollow structure formed on days 5-6 that implants into the uterine wall.

Embryo

The developing organism during weeks 3–8.

Foetus

The developing organism from week 9 onward.

Gastrulation

The process of primary germ layer formation (ectoderm, mesoderm, and endoderm) occurring post-implantation.

Ectoderm

Germ layer that forms the epidermis of the skin.

Mesoderm

Germ layer that forms the skeleton, muscles, heart, blood, gonads, kidneys, and dermis.

Endoderm

Germ layer that forms the lining of the digestive and respiratory tracts, liver, pancreas, thymus, and thyroid.

Totipotent stem cells

Cells that can give rise to any other cell type, such as the zygote and early blastomere.

Pluripotent stem cells

Cells capable of giving rise to all cells in the organism's body.

Cell determination

The commitment of a cell to a specific pathway, which occurs before differentiation.

Simple epithelium

Epithelial tissue classification that is one layer thick.

Stratified epithelium

Epithelial tissue classification that is two or more layers thick.

Squamous

Epithelial cells shaped like they are squashed.

Cartilage

Strong, flexible connective tissue made of chondrocytes within ground substance, containing no blood supply.

Osteocytes

Mature bone cells that sit within a matrix strong due to calcium phosphate crystals.

Cardiac Muscle

Small, interconnected striated cells joined by intercalated discs (gap junctions) that act as a single functional unit.

Central Nervous System (CNS)

Consists of the brain and spinal cord; functions to integrate and process information.

Peripheral Nervous System (PNS)

Carries sensory (afferent) information to the CNS and command (efferent) information from the CNS to the body.

Neuroglia

Supporting cells of the nervous system that nourish, protect, and maintain neurons but do not primarily conduct impulses.

Axon hillock

The start of the axon where information received by dendrites is accumulated and can trigger an action potential.

Synaptic cleft

The gap across which neurotransmitters are released from the axon terminal to the postsynaptic membrane.

Gray matter

Regions of the nervous system with a high density of neuronal cell bodies; includes cortex, nucleus, and ganglion.

White matter

Regions of the nervous system with a high density of axons; includes tracts and nerves.

Resting potential

The electrical charge of a resting nerve cell membrane, measured at approximately $-70\,mV$.

Action potential

An electrical impulse generated by the rapid movement of $\text{Na}^+$ and $\text{K}^+$ into and out of the cell.

Sensory Neurons

Afferent neurons that deliver information from sensory receptors to the CNS.

Motor Neurons

Efferent neurons that deliver movement information from the CNS to the body's effectors.

Thalamus

Part of the diencephalon that filters and relays sensory information to the cerebral cortex; involved in consciousness and sleep.

Hypothalamus

Major regulator of homeostasis; controls autonomic function, body temperature, emotions, behavior, thirst, and hunger.

Medulla Oblongata

Brainstem region containing autonomic centers for regulation of cardiovascular, respiratory, and digestive activities.

Enteric Nervous System

A network of neurons in the walls of the digestive tract that operates without instructions from the brain or spinal cord.