Anatomy

Anatomy

study of the structure and organization of living organisms.

• It is a branch of biology that focuses on the identification, description, and understanding of the physical structures of organisms.

• It can give insights into how different parts of the body are organized and function.

Gross anatomy, microscopic anatomy (histology), comparative anatomy and developmental anatomy.

What are the sub-disciplines of anatomy?

Gross Anatomy

• also known as macroscopic anatomy

• the examination and dissection of organs, tissues, and structures visible to the naked eye.

• It involves the study of the body at a larger scale and focuses on the relationships between different organs and systems.

Microscopic Anatomy (Histology)

deals with the study of tissues and cells at a microscopic level.

• It involves the use of microscopes to examine the structures and functions of cells, tissues, and organs in detail.

• helps in understanding the organization and characteristics of different tissues, such as epithelial, muscular, nervous, and connective tissues.

Comparative Anatomy

• the study of anatomical structures across different species to identify similarities and differences.

• By comparing the anatomical features of various organisms, scientists can gain insights into evolutionary relationships and adaptations.

Developmental Anatomy

• The study of the structural changes that occur during an organism's development from conception to adulthood.

• It explores how different structures form and mature over time, providing valuable information about the growth and development of organisms

Anatomical Position

• The standard reference position for describing the human body.

• The body is upright, facing forward, with arms at the sides and palms facing forward.

• This position provides a common starting point for anatomical descriptions.

Anterior (ventral)

towards the front of the body.

Posterior (dorsal)

towards the back of the body.

Superior

a structure located above or higher in position.

Inferior

a structure located below or lower in position.

Proximal

a structure that is closer to the point of attachment or the trunk of the body.

Distal

a structure that is farther away from the point of attachment or the trunk of the body.

Medial

Refers to a structure closer to the midline of the body

Lateral

Refers to a structure farther away from the midline of the body.

Sagittal Plane

Divides the body into left and right portions.

Frontal (Coronal) Plane

Divides the body into front and back portions.

Transverse (Horizontal) Plane

Divides the body into upper and lower portions.

Regions

The body is divided into various regions for descriptive purposes, such as the head, neck, thorax, abdomen, pelvis, upper limbs, and lower limbs.

Quadrants

• The abdomen is commonly divided into four quadrants: right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ).

• These quadrants help in localizing abdominal pain or determining the location of organs.

Cranial cavity

houses the brain

spinal cavity

houses the spinal cord.

thoracic cavity

houses the heart, lungs, and other thoracic organs.

abdominopelvic cavity

houses the abdominal and pelvic organs

Human body

composed of several organ systems, each with its own set of organs and functions. These organ systems work together to maintain the overall health and functioning of the body.

11

The body consists of ___ major organ systems.

Digestive System

• Mechanical and chemical breakdown of food, absorption of nutrients, elimination of waste products.

• Major organs include the mouth,

  esophagus, stomach, small intestine,

  large intestine, rectum, and anus,

• Associated organs include the liver,

  pancreas, appendix, and gallbladder.

Peristalsis

coordinated muscle contractions to move the food in the digestive tract

Chyme

a mixture of food and digestive juices that is produced in the stomach

Bolus

Food that has been chewed and mixed in the mouth with saliva

Villi

The small intestine is lined with tiny finger-like projections called villi, which increase the surface area available for absorption

liver

The ______ produces bile, which helps break down fats in the small intestine.

pancreas

secretes hormones that regulate blood sugar levels.

Gallbladder

stores and releases bile into the small intestine as needed.

Muscular System

Movement and locomotion, maintenance of posture, generation of heat, and support for internal organs.

Skeletal muscles, smooth muscles, cardiac muscle.

Three organs in muscular system.

Skeletal Muscles

• The largest and most numerous type of muscle cells in the body

• They are responsible for voluntary movements such as walking, jumping, and lifting weights.

• These cells are multinucleated and have a striated appearance due to the arrangement of actin and myosin filaments within the cell.

Smooth Muscles

• found in the walls of internal organs such as the digestive system, respiratory system, and blood vessels.

• They are responsible for involuntary movements such as the contraction of the stomach during digestion or the constriction of blood vessels in response to stress or injury.

• spindle-shaped and have a single nucleus.

Cardiac Muscles

• also known as cardiomyocytes, are found in the heart.

• Responsible for the rhythmic contraction of the heart that pumps blood throughout the body.

• These cells are also striated, branched, and have a single nucleus.

Integumentary System

Protection against external threats, regulation of body temperature, sensation, vitamin D synthesis.

• Organs are skin, hair, nails, sweat glands, sebaceous glands.

Epidermis

outermost layer and composed of keratinocytes.

Dermis

second layer composed of collagen, glands, and elastic fibers.

Hypodermis

the subcutaneous layer that contains fat and connective tissues.

Hair

composed of keratin and grows from hair follicles located in the dermis.

Nails

composed of keratin and grow from nail beds located in the epidermis.

Sweat glands

produce sweat, which helps regulate body temperature and eliminate waste products.

Oil gland

produce sebum, which helps keep the skin and hair moisturized.

Mammary glands

produce milk in females.

Lymphatic System

• Immune defense, removal of excess fluids and waste materials, absorption of fats from the digestive system

• Organs: Lymph nodes, lymphatic vessels, spleen, thymus, tonsils, bone marrow.

Lymphatic vessels

• thin-walled vessels that transport lymph a clear fluid that contains white blood cells, throughout the body.

• they are similar in structure to veins and have one-way valves that prevent backflow.

Lymph nodes

• small, bean-shaped structures located throughout the body along lymphatic vessels.

• They filter lymph, removing bacteria, viruses, and other foreign substances.

• Lymphocytes are also found in ____________ and help identify and destroy foreign invaders.

Spleen

• largest lymphatic organ and is located in the upper left part of the abdomen.

• it filters blood, removing old or damaged red blood cells, and also helps fight infections.

Thymus

a gland located in the chest that plays a key role in the development and maturation of T-lymphocytes.

T-lymphocytes

a type of white blood cell that helps defend against infection.

Tonsils

are a pair of soft tissue masses located at the rear of the throat (pharynx).

Bone marrow

spongy tissue found inside bones that produces blood cells, including lymphocytes

Endocrine System

• Regulation of body processes through the production and release of hormones, maintenance of homeostasis.

• Organs: Pituitary gland, thyroid gland, adrenal glands, pancreas, gonads (testes and ovaries), and others.

• A complex network of glands and organs that secrete hormones into the bloodstream to regulate various physiological processes in the body.

• It relies on chemical messengers called hormones to communicate with target cells and tissues.

Pituitary gland

• also known as the "master gland," is located at the base of the brain and is responsible for regulating the activity of other endocrine glands.

• It produces several hormones, including:

  • Growth hormone (GH), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), and Prolactin.

Growth hormone (GH)

stimulates growth and development in children and adolescents.

Thyroid-stimulating hormone (TSH)

regulates the activity of the thyroid gland.

Adrenocorticotropic hormone (ACTH)

regulates the activity of the adrenal glands.

Prolactin

stimulates milk production in lactating women.

Pineal Gland

located in the center of the brain, between the two hemispheres, and is shaped like a pinecone. It is for regulating the body's sleep-wake cycle, also known as the circadian rhythm.

Circadian Rhythm

body's sleep-wake cycle

Melatonin

It is produced in response to darkness and helps regulate the timing and quality of sleep. It is also involved in regulating other physiological processes, such as body temperature, blood pressure, and immune function.

Thyroid Gland

is located in the neck and produces hormones that regulate metabolism. The two primary _______ hormones are: Triiodothyronine (T3) and Thyroxine (T4):

Triiodothyronine (T3) and Thyroxine (T4)

increases metabolic rate and is necessary for growth and development.

Parathyroid Gland

are small glands located in the neck.

Parathyroid hormone (PTH)

regulates calcium levels in the body.

Adrenal Gland

are located on top of the kidneys and produce several hormones, including: cortisol, aldosterone, epinephinr and norepinephrine, epinephrine/adrenalin and norepinephrine.

Cortisol

regulates metabolism and helps the body respond to stress.

Aldosterone

regulates salt and water balance in the body.

Epinephrine and norepinephrine

help the body respond to stress.

Epinephrine/Adrenalin

act mainly as a hormone.

Norepinephrine

acts as a neurotransmitter.

Pancreas

is a glandular organ located behind the stomach that produces several hormones, including insulin and glucagon.

Insulin

regulates blood sugar levels by promoting the uptake of glucose by cells.

Glucagon

raises blood sugar levels by promoting the breakdown of glycogen in the liver.

Gonads

(testes in males and ovaries in females) produce several hormones that regulate reproductive functions, including: testosterone and estrogen and progesterone.

Testosterone

responsible for male sexual development and function. It regulates sex drives, bone mass, fat distribution, muscle mass and strength, and the production of sperm.

Estrogen and progesterone

responsible for female sexual development and function. It regulates the uterus and the menstrual cycle.

Nervous System

Control and coordination of body activities, reception and interpretation of sensory information.

• Organs: Brain, spinal cord, nerves, sensory organs

Central nervous system (CNS)

made up of the brain and spinal cord.

Peripheral nervous system (PNS)

composed of all the nerves and ganglia outside of the CNS.

Somatic Nervous System and Autonomic Nervous System

The Peripheral Nervous System is divided into two main parts:

Somatic Nervous System

controls voluntary movements and sensations, such as walking and feeling a touch on your skin.

Autonomic Nervous System

controls involuntary functions, such as heart rate, breathing, and digestion.

Sensory System and Motor System

Somatic Nervous System is divided into two:

Sensory System

Peripheral→CNS

Motor System

CNS→Peripheral

Parasympathetic and Sympathetic

Autonomic Nervous System is divided into two:

Parasympathetic

“rest and digest” and occur when the body is at rest (digestion, relaxation, and slowing the heart rate.)

Sympathetic

"fight or flight" response when the body is faced with a perceived threat or stressor. (Increasing heart rate, respiration rate, and blood pressure)

Neurons

have three main parts: the cell body, dendrites, and axon.

Cell body

contains the nucleus and other organelles.

Dendrites

short, branched extensions that receive signals from other neurons.

Axon

long, thin extension that transmits signals to other neurons or to muscles or glands.

Synapses

Neurons communicate with each other at ________, where chemical neurotransmitters are released from one neuron and bind to receptors on another neuron.

Neurotransmitters

chemical messengers that are released from neurons and bind to receptors on other cells.

Acetylcholine

involved in muscle movement, learning, and memory.