Exam #3 with chapter 14

Endocrine gland

Cells, tissues and organs that make up the endocrine system

Are ductless

Secrete hormones into the bloodstream

Exocrine gland

Secrete into ducts/tubes that lead to a body surface

Secrete externally

Deliver their products directly to a specific site

EXAMPLE: sweat glands

Comparison between Nervous and Endocrine System

Both function in communication

Both communicate via chemicals that bind to receptor molecules

Differences between Nervous and Endocrine System

Nervous System - releases Neurotransmitters into synapses

Endocrine System - secretes hormones into bloodstream

Steroid hormones

Steroids are lipids containing complex rings of carbon and hydrogen atoms

All steroid hormones are produced from cholesterol

EXAMPLE: sex hormones (testosterone, estrogen) and adrenal cortex hormones (cortisol, aldosterone)

Steroid and thyroid hormones

Have poor water-solubility

Can diffuse through a lipid bilayer of cell membranes

Bind to receptors inside the cell - usually in the nucleus

Non-steroid hormones

Cannot penetrate the lipid bilayer of cell membranes

Bind to receptors on the target cell membrane

First messenger: hormone

Second messenger: the chemical that induces changes leading to the hormone’s effect (cyclic adenosine monophosphate; cAMP)

Pituitary gland

Lies at the base of the brain in sella turcica of sphenoid bone

Attached to hypothalamus by pituitary stalk

Anterior pituitary hormone

Produced in the anterior lobe; hormones are released in response to a releasing hormone from the hypothalamus

Anterior pituitary hormone - hormones secreted

Prolactin (PRL)

Thyroid-stimulating hormone (TSH)

Anterior pituitary hormone - hormones action

Prolactin: promotes milk production in females, uncertain function in males

Thyroid-stimulating hormone: stimulates secretion of thyroid hormones (T3 and T4) from thyroid gland

Hypopituitary dwarfism

Deficiency of growth hormone during childhood

Short stature, but body proportions and mental development are normal

Treatment must start before bones completely ossify

Gigantism

Caused by over secretion of growth hormone during childhood

Hight may exceed 8 ft and may have other metabolic problems

Often caused by pituitary tumor

Acromegaly

Caused by over secretion of growth hormone during adulthood after epiphyseal ossification

No increase in height, but bones thicken

Enlargement of tongue, nose, hands, feet, jaw, heart, and thyroid gland

Posterior pituitary hormone

Consists of nerve fibers from hypothalamus and neuroglia

2 hormones are produced by neurons in the hypothalamus; stored and released by PPH

Hormones are transported to the PPH via the pituitary stalk

Posterior pituitary hormone - hormones secreted

Antidiuretic hormone (ADH)

Oxytocin (OT)

Posterior pituitary hormone - hormones action

Antidiuretic hormone: causes kidneys to reduce water excretion; in high concentration → raises blood pressure

Oxytocin: contracts smooth muscle in the uterine wall; forces liquid from the milk glands into the milk ducts → ejects milk

Thyroid gland

Lies below the larynx; anterior and lateral to the trachea

Has special ability to remove iodine from blood

Thyroid gland - hormones secreted

T4 (thyroxine)

T3 (triiodothyronine)

Calcitonin

Thyroid gland - hormones actions

T4 (Thyroxine): increases rate of energy release from carbs; increases rate of protein synthesis; accelerates growth; stimulates activity in nervous system

T3 (Triiodothyronine): same as T4, but 5x more powerful

Calcitonin: involved in helping to regulate levels of calcium and phosphate in the blood; acts to reduce calcium levels in the blood

Parathyroid glands

Located on the posterior surface of the thyroid gland

Parathyroid gland - hormone secreted

Parathyroid hormone/parathormone (PTH)

Parathyroid gland - hormone action

Parathyroid hormone/parathormone (PTH): regulates Ca^+2 and PO4^-2 concentrations in blood

Adrenal gland/suprarenal gland

Closely associated with the kidneys

Sit like a cap on each kidney

Adrenal gland - hormones secreted

Adrenal cortex

Adrenal medulla

Adrenal medulla

Central portion of glands, secretes amine hormones

Flight/fight response

Adrenal cortex

Outer portion of gland, secretes steroid hormones

Deals with stress

Pancreas

Elongated, flattened organ

Posterior to stomach

Has both an endocrine and an exocrine gland

Endocrine function: secretes hormones into body fluids

Exocrine function: secretes digestive juices through a duct

Pancreas - hormones secreted

Glucagon

Insulin

Somatostatin

Pancreas - hormones action

Glucagon: stimulates the liver to break down glycogen and convert non-carbs into glucose; stimulates breakdown of fats (increases blood glucose when too low)

Insulin: allow glucose to enter cells to be used as energy and to maintain the amount of glucose found in the bloodstream within normal levels (lowers blood glucose when too high)

Somatostatin: helps regulate glucose metabolism

Pineal gland

Located on posterior part of brain

Pineal gland - hormone secreted

Melatonin

Pineal gland - hormone action

Regulates circadian rhythms

Thymus gland

Located on medial part of chest

Thymus gland - hormone secreted

Thymosin

Thymus gland - hormone action

Produces T-lymphocytes (T-cells)

Important in the role of immunity

Reproductive organs

Ovaries produce estrogens and progesterone

Testes produce testosterone

Placenta produces estrogens, progesterone and gonadotropin

Endocrine system

Regulates all biological processes in the body from conception to adulthood to old age

Cardiovascular

Refers to both heart and blood vessels

Pumping action of heart transports blood through blood vessels

2 Circuits of blood flow

Pulmonary circuit

Systemic circuit

Pulmonary circuit

Transports oxygen-poor blood from heart to lungs and back to heart

In lungs, blood picks up O2 and drops off CO2

Systemic circuit

Transports oxygen-rich blood from heart to all body cells and back to heart

Blood delivers nutrients to cells and removes wastes

Disorders of the cardiovascular system

Heart murmur

Heart attack

Heart murmur

A blowing, whooshing or rasping sound heard during a heartbeat

Caused by turbulent (rough) blood flow through the heart valves/near the heart

Heart attack

Flow of blood to the heart is severely reduced or blocked

The blockage is due to a buildup of fat, cholesterol and other substances in the heart arteries

Artery (blood vessel) - structure

Thick, strong wall, thicker than walls of veins

Has 3 layers: tunica interna, tunica media, tunica externa

Arteriole (blood vessel) - structure

Thinner muscular walls and elastic layers than arteries

Only contain a few muscle fibers in their walls

Capillary (blood vessel) - structure

Smallest diameter blood vessel

Connect the smallest arterioles and the smallest venules

Venule (blood vessel) - structure

Microscopic vessel

Thinner walls and less smooth muscle than arterioles

Vein (blood vessel) - structure

Thinner walls than arteries

Has 3 layers/tunics

Have flap-like valves

Artery (blood vessel) - function

Transport blood under high blood pressure away from the heart

Give rise to smaller arterioles

Arterioles (blood vessel) - function

Reduces the pressure and velocity of blood flow to enable gas and nutrient exchange to occur within the capillaries (control the diameter)

Capillary (blood vessel) - function

Site of gas exchange

Are semi-permeable

Venule (blood vessel) - function

Transport blood from the capillaries to veins

Vein (blood vessel) - function

Carry blood under relatively low pressure back to the heart

Function as blood reservoirs

Right atrium (heart chamber)

Receives blood returning from systemic circuit (from superior/inferior vena cava and coronary sinus)

Pumps blood to right ventricle

Right ventricle (heart chamber)

Receives blood from the right atrium

Pumps blood to lungs

Left atrium (heart chamber)

Receives blood from the pulmonary veins

Pumps blood to left ventricle

Left ventricle (heart chamber)

Receives blood from the left atrium

Pumps blood to systemic circuit

Cardiac cycle

Events of a heartbeat

Pressure in the heart chambers rise and fall

Pressure changes open and close the valves

Systole

Heart muscle contracts and pumps blood out of the chambers

Diastole

Heart muscle relaxes after contraction and allows the chambers to be filled with blood

Atrial systole & ventricular diastole

Ventricles are relaxed

The AV valves open and the semilunar valves close

About 70% of blood flows passively from atria into ventricles

Atrial systole pushes remaining 30% of blood into the ventricles - causes ventricular pressure to increase

Ventricular systole & atrial diastole

The AV valves close

The chordae tendinea prevent the cusps of the valves from bulging too far backward into atria

Atria relaxes

Blood flows into atria from the vena cava and pulmonary veins

Blood flows into the pulmonary trunk and aorta

Cardiac conduction system

Group of clumps and strands of specialized cardiac muscle tissue

Initiates and distributes impulses throughout the myocardium

Coordinates the events of the cardiac cycle

Major components - cardiac conduction system

SA (sinoatrial) node

Internodal atrial muscle

Junctional fibers

AV (atrioventricular) node

AV (atrioventricular) bundle

Left and right bundle branches\]

Purkinje fibers

SA (sinoatrial) node

Pacemaker

Initiates rhythmic contractions of the heart

Internodal atrial muscle

Conducts impulses from SA node to atria

Junctional fibers

Conduct impulses from SA node to AV node

AV (atrioventricular) node

Conducts impulses to AV bundle

Delays impulse so atria can finish contracting before ventricles contract

AV (atrioventricular) bundle

Conducts impulses rapidly between AV node and bundle branches

Left and right bundle branches

Split off from AV bundle

Conduct impulses to purkinje fibers on both sides of heart

Purkinje fibers

Large fibers that conduct impulses to ventricular myocardium

Electrocardiogram (ECG, EKG)

Recording of electrical changes that occur in the myocardium during the cardiac cycle

Used to assess the heart’s ability to conduct impulses

P wave

Atrial depolarization

Occurs just prior to atrial contraction

QRS complex (3 waves)

Ventricular depolarization

Occurs just prior to ventricular contraction

T wave

Ventricular repolarization

Occurs just prior to ventricular relaxation

Steps in signal transduction pathway

Receptor: process by which a cell detects a signal in the environment

Transduction: process of activating a series of proteins inside the cell from the cell membrane

Response: change in behavior that occurs in the cell as a result of the signal

Lymphatic system

Defends body against infection by pathogens

Contains a network of vessels that assist in circulating fluids

Closely associated with the cardiovascular system

Functions - lymphatic system

Transports excess fluid away from the interstitial spaces (space between cells) and returns it to bloodstream

Absorbs lipids from digestive system and transports them to bloodstream

Defends the body against diseases

Lymph

S: colorless fluid containing white blood cells

F: managing the fluid levels in the body

Lymphatic vessel

S: thin tube

F: carries lymph and white blood cells through lymphatic system

Lymph node

S: small bean-shaped structure

F: filter substances which travel through the lymphatic fluid

Thoracic duct

S: main vessel of lymphatic system

F: collects and transports lymph back into the circulatory system

Right lymphatic duct

S: combination of neck muscles; formation varies

F: drains fluid that has leaked from the blood vessels into the tissues; empties it back into the bloodstream via lymph nodes

Thymus gland

S: asymmetrical flat shape with a lobular structure

F: makes white blood cells (T-cells) which protect the body against infections

Spleen

S: consists of two types of tissue: white pulp and red pulp

F: controls the level of blood cells; removes any old or damaged red blood cells

Pathogens

Disease-causing agents

Bacteria, viruses and complex microorganisms

Innate (non-specific) defenses

General defenses

Protect against many types of pathogens

Adaptive (specific) defenses

Immunity

More specific and precise - targets specific antigens

Carried out by lymphocytes that recognize certain foreign molecules

Mechanical barriers

First line of defense

Skin and mucous membranes form mechanical barriers

EXAMPLES: hair traps, tears, saliva, urine

Chemical barriers

Second line of defense

* Enzymes
* Interferons
* Complement

Natural kill (NK) cells

Second line of defense

Defend against viruses and cancer cells by secreting cytolytic substances (perforins: disintegrate cell membranes)

Inflammation

Second line of defense

Walls off infection site and stops spread of infection

Phagocytosis

Second line of defense

Removes foreign particles from the lymph

* Neutrophils
* Monocytes

Fever

Second line of defense

Produces cells that secrete interleukin-1 (endogenous pyrogen) which is a fire maker from within

Adaptive (specific)

Third line of defense

Immunity

* Cell-mediated immune response
* Humoral immune response

Antigens

Non-self molecules that elicit an immune response

3 types of blood cells

red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

function of red blood cell

Red blood cells, also known as erythrocytes, are responsible for carrying oxygen from the lungs to the body's tissues and transporting carbon dioxide from the tissues to the lungs to be exhaled.